My blog moniker notwithstanding, the surname Slade is not related to the verb to slay, rather it derives from the Old English word slǣd (or slēd, slēad), a neuter common noun (see Bosworth & Toller:881), which can denote a range of different topographical features (the exact sense apparently depending on the dialect):
"A valley, dell, or dingle; an open space between banks or woods; a forest glade; a strip of greensward or of boggy land."
In Old English the word occurs primarily in charters (documents recording a grant of land or other privilege), used in the description of property boundaries:
Of þere ealdan dic a be graue to wulf slæde."From the old ditch, by the grove, to the Wolf-Slade."[Ch 661 (Birch 1009) B15.8.312: 0018(10)]Þanon norð on wiðig slæd."Thence north to the slade of willows."[Ch 345 (Birch 550) B15.8.82: 0006 (3)]Andlang englunga dene swa wæter wile yrnan in hæþenan byrigels a be wyrtwalan in barfodslæd and swa on timberslæd in stepacnolles scydd on hanslædes heafdan innan grenan weg."Along Engel's Dell, as the water runs, to the heathen burials by the lower-side of the Boarfodder Slade and so on to the Timber-Slade (wooded valley?) in the twist(?) of the high knoll in upper-side of the Rooster-Slade within the green path."[Ch 104 (Birch 216) B15.8.15: 0002 (1)]
In Middle English it appears with similar meanings; below follow quotations where slade seems to mean something like "valley":
He dremeth ofte..hou he clymbeth up the banckes And falleth into Slades depe."He dreams often...how he climbs up the banks and falls into the slade's deep."[(1393)John Gower, Confessio Amantis, IV.2727]And soo he [Launcelot] rode in to a grete forest all that day / and neuer coude fynde no hyghe waye / and soo the nyght felle on hym / and thenne was he ware in a slade of a pauelione of reed sendel."And so Lancelot rode into a great forest all that day, and never could find no high way, and so the night fell on him, and then he became aware of a pavilion of red linen in a slade."[(1470)Syr Thomas Malory, Le Morte Darthur, VI.5]There by a lytyll slad sir Launcelot wounded hym sore nyghe unto the deth."There by a little slade Sir Lancelot wounded him sorely, nearly unto death."[(1470)Syr Thomas Malory, Le Morte Darthur, VI.5]For drede lest þou be ouerthrowe And falle so depe into the slade, That euer after it myght turne to shade."And fear least you be overthrown and fall so deep into the slade that ever after it might turn to shade."[(1475)Peter Idley, Instructions to His Son, 1.846]
And my favourite---essentially slayed 'em in a slade, with alliterating slogh ("slay"), sleghly ("cunningly") and slade---found in an early English translation of The Aeneid (where in þe slade moue means "in the mouth of the valley"):
Þai..Slogh hom doun sleghly in þe slade moue."They struck them down ('slayed them down') cunningly in the mouth of the slade."[(1540)John Clerk of Whalley Lancashire, The Gest Hystoriale of the Destruction of Troy, 7005]
We also find slade used metaphorically in the sense "slopes/valleys of clouds", as in:
The skyes in her coloures rake, Þe therke sladdes of clowdes blake: This reioyceth me above."The sky rushing in her colours, the dark slades of black clouds: this cheers me up."[(1500), A speech of delight, 19-21]
All of these common noun usages of slade appear to be archaic/obsolete in modern English (though perhaps they survive in certain dialects?). The most recent example in Oxford English Dictionary for slade as a common noun is from the end of the 19th-century:
Over the slade they took their way, where the purple carpet was patterned with round hollows.[(1899) A. MORRISON, To London Town 5]
The usual form of the surname, Slade (rather than slæd or slad), derives from the dative singular form (the case often employed after prepositions like in, from etc.), reflecting the fact that the surname originally denoted the place of residence, i.e. "the person who lives in a slade". Indeed in late Old English and Middle English we find records like:
Robertus de la Slade. ("Robert of the Slade")[(1221)Calendar of the Patent Rolls Preserved in the Public Record Office, (during the reign of) Henry III]Laur. de Slade. ("Laurence of Slade")[(1296)The Three Earliest Subsidies for the County of Sussex in the years 1296, 1327, 1332]Johannes atte Slade. ("John at the Slade")[(1345)Rymer's Foedera (1816-69) :: Foedera, conventiones, literae]
The forms de la and de reflect Norman French patterns (interestingly, slade is treated as feminine in Norman French; though of course French has no grammatical neuter gender so it had to assign slade to either masculine or feminine). Atte is a contracted form of at þe "at the".
Anglo-Saxon kingdoms (including Essex)
The earliest use of Slade as a proper noun is the name of the early Anglo-Saxon king of Essex, Sledd (or Sledda), who married Ricula, the sister of King Æthelbert of Kent. One of the East Saxon genealogies for Sledd is given below:
Offa sighering, sighere sigberhting, sigberht sawearding, saweard saberhting, saberht sledding, sledd æscwining, æscwine offing, offa bedcing, bedca sigefugling, sigefugl swæpping, swæppa antsecging, antsecg gesecging, gesecg seaxneting."Offa, son of Sighere, son of Sigberht, son of Saweard, son of Saberht, son of Sledd, son of Æscwine, son of Offa, son of Bedca, son of Sigefugl, son of Swæppa, son of Antsecg, son of Gesecg, son of Seaxneat."[London, British Library, Add. MS 23211 (9th-c.?), in Sweet:179]
The form Sledd instead of Slæd appears to reflect the changes in the system of front vowels found in the Old English of Kent (neighbouring Essex) during the 9th-century, which included the changes æ > e , ǣ > ē (see Campbell:§288-§291). Although Sledd's father Æscwine/Eorcenwine is sometimes credited with the foundation of the kingdom, the genealogies included in the works of William of Malmesbury and John of Worcester (Chronicon B) treat Sledd the first king of Essex. In the genealogy cited above, Sledd is treated as a descendant of Seaxnēat, the mythical founder of the Saxons. (On King Sledd of Essex, see further Yorke.)
However, in more modern times, the surname Slade appears to have been most commonly found in the southwest of England, particularly in Devon.
As shown by the map above, Slades were also found in the neighbouring county of Somerset, where another "B. Slade", Sir Benjamin Julian Alfred Slade, Bt., has his ancestral seat, Maunsel House (which his ancestors appear to have acquired in the 18th-century), where Geoffrey Chaucer is said to have written part of Canterbury Tales.
Other famous Slades include Sir Thomas Slade, the naval architect who designed the HMS Victory, Lord Nelson's flagship at the Battle of Trafalgar in 1805; Felix Slade, who endowed professorships at Oxford, Cambridge, and University College London, as well as endowing scholarships which led to the establishment of the Slade School of Fine Art in London; and Madeleine Slade, daughter of the British Rear-Admiral Sir Edmond Slade, who left England for India to work with Mohandas Gandhi (who gave her the name Mirabehn) during the Quit India movement.
For more genealogical information on Slades in the USA and UK, see Jim Slade's excellent site SladeGenealogy.net. [On the Maryland Slades, see the genealogy research of the late John Pearce available here.]
Earlier etymology of SLADE:
The range of meanings we find for the word slade seem to point to its original sense as being something like "slope", compare the cognate dialectal Norwegian slad [neuter] (also slade[masculine]), "a slope, a hollow". And thus the Proto-Germanic root underlying slade must be cognate with Proto-Germanic*slid- "to slip, slide" (from Proto-Indo-European *sleidh-), from which root is derived English slide (from Old English slīdan) as well as sled (from Middle Low German sledde) and sleigh (from Middle Dutch slēde "sled"), see Watkins:80.
The Proto-Indo-European form *sleidh- is an extended form of the more basic Proto-Indo-European root *(s)lei-, from which, with other extensions, we derive a number of other words in English, including lime (as in bird-lime, on which see here), and slip. The latter word, slip, is also cognate with the name given to the eight-legged horse, Sleipnir "the slippery(?), the glider(?)", belonging to the Norse god Odin (more properly Óðinn, whose name in Old English is Wōden; both from Proto-Germanic *Wōd-inaz "raging, mad, inspired", itself from the Proto-Indo-European root *wet- "to blow, spiritually inspire"; see Watkins:101), as depicted below:
[Odin riding Sleipnir, 18th-century illustration in MS NKS 1867 4°, Danish Royal Library]
[Odin riding Sleipnir, 8th/9th-century Ardre picture stone (Gotland, Sweden)]
Bosworth, Joseph and T. Northcote Toller. 1898. An Anglo-Saxon dictionary. London: Oxford University Press.
Sweet, Henry. 1885. The oldest English texts. London: Early English Text Society.
Campbell, Alistair. 1959. Old English grammar. Oxford: Clarendon.
Yorke, Barbara. 1985. "The kingdom of the East Saxons". Anglo-Saxon England 14:1-36.