1580s, "toward the shore," from a- (1) + shore (n.). The meaning "on the shore" is from 1630s. Middle English had ashore (late 15c.), but it meant "on a slant," literally "propped up," from shore (v.).
Entries linking to ashore
a- 1
prefix or inseparable particle, a conglomerate of various Germanic and Latin elements.
In words derived from Old English, it commonly represents Old English an "on, in, into" (see on (prep.)), as in alive, above, asleep, aback, abroad, afoot, ashore, ahead, abed, aside, obsolete arank "in rank and file," etc., forming adjectives and adverbs from nouns, with the notion "in, at; engaged in." In this use it is identical to a (2).
It also can represent Middle English of (prep.) "off, from," as in anew, afresh, akin, abreast. Or it can be a reduced form of the Old English past participle prefix ge-, as in aware.
Or it can be the Old English intensive a-, originally ar- (cognate with German er- and probably implying originally "motion away from"), as in abide, arise, awake, ashamed, marking a verb as momentary, a single event. Such words sometimes were refashioned in early modern English as though the prefix were Latin (accursed, allay, affright are examples).
In words from Romanic languages, often it represents reduced forms of Latin ad "to, toward; for" (see ad-), or ab "from, away, off" (see ab-); both of which by about 7c. had been reduced to a in the ancestor of Old French. In a few cases it represents Latin ex.
[I]t naturally happened that all these a- prefixes were at length confusedly lumped together in idea, and the resultant a- looked upon as vaguely intensive, rhetorical, euphonic, or even archaic, and wholly otiose. [OED]
shore n.
"land bordering a large body of water," c. 1300, from Old English scora, sceor- (in place-names) or from Middle Low German schor "shore, coast, headland," or Middle Dutch scorre "land washed by the sea," all probably from Proto-Germanic *skur-o- "cut," from PIE root *sker- (1) "to cut."
This is the usual theory, "but the etymological notion is not easy to determine" [OED]. It has been proposed as meaning "division" between land and water, but if the word began on the North Sea coast of the continent, it might as well have meant originally "land 'cut off' from the mainland by tidal marshes" (compare Old Norse skerg "an isolated rock in the sea," related to sker "to cut, shear").
Old English words for "coast, shore" were strand (n.), waroþ, ofer. Few Indo-European languages have such a single comprehensive word for "land bordering water" (Homer uses one word for sandy beaches, another for rocky headlands).
General application to "country near a seacoast" is attested from 1610s. In law, typically the tract between the high- and low-water marks (1620s). Shore-bird is attested from 1670s; the sailor's shore-leave by 1845.
shore v.
mid-14c., shoren, "to prop, support with or as if by a prop," from or related to shore (n.) "a prop, a support" (late 13c.); words of obscure etymology though widespread in Germanic (Middle Dutch schooren "to prop up, support;" Middle Low German schore "a barrier;" Old Norse skorða "piece of timber set up as a support"). Related: Shored; shoring.
The noun survives in technical senses, "post or beam for temporary support of something" (mid-15c.), especially an oblique timber to brace the side of a building or excavation.