late 14c., "sand table for drawing, calculating, etc.," also "art of calculating with an abacus," from Latin abacus, from Greek abax (genitive abakos) "counting table, board for drawing," a word of uncertain etymology. It is said to be from a Semitic source, such as Phoenician or Hebrew abaq "sand strewn on a surface for writing," literally "dust," from the Semitic root a-b-q "to fly off," but Beekes and others find this "semantically weak."

Originally a drawing board covered with dust or sand on which mathematical equations or calculations could be traced and erased. In reference to the other type of abacus, a counting frame with beads or balls strung on wires or rods, it is attested from 17c. or later in English. Both types were known in antiquity across Eurasia. Related: Abacist (late 14c.)

late 14c., used in Revelation ix.11 of "the angel of the bottomless pit," and by Milton of the pit itself, from Hebrew Abhaddon, literally "destruction," from abhadh "he perished." The Greek form was Apollyon.

"self-devoted" to some practice or purpose (usually evil), late 14c., past-participle adjective from abandon (v.) in the reflexive sense. Hence, in a general way, "shamelessly wicked" (1690s). Meaning "deserted, forsaken" is from late 15c.

late 14c., "to give up (something) absolutely, relinquish control, give over utterly;" also reflexively, "surrender (oneself), yield (oneself) utterly" (to religion, fornication, etc.), from Old French abandonner "surrender, release; give freely, permit," also reflexive, "devote (oneself)" (12c.).

The Old French word was formed from the adverbial phrase à bandon "at will, at discretion," from à "at, to" (from Latin ad; see ad-) + bandon "power, jurisdiction," from Latin bannum, "proclamation," which is from a Frankish or other Germanic word, from Proto-Germanic *bannan- "proclaim, summon, outlaw" (things all done by proclamation); see ban (v.).

Mettre sa forest à bandon was a feudal law phrase in the 13th cent. = mettre sa forêt à permission, i.e. to open it freely to any one for pasture or to cut wood in; hence the later sense of giving up one's rights for a time, letting go, leaving, abandoning. [Auguste Brachet, "An Etymological Dictionary of the French Language," transl. G.W. Kitchin, Oxford, 1878]

Meaning "to leave, desert, forsake (someone or something) in need" is from late 15c.  Related: Abandoned; abandoning.

Etymologically, the word carries a sense of "put (something) under someone else's control," and the earliest appearance of the word in English is as an adverb (mid-13c.) with the sense "under (one's) control," hence also "unrestricted."

Again, as that which is placed at the absolute command of one party must by the same act be entirely given up by the original possessor, it was an easy step from the sense of conferring the command of a thing upon some particular person to that of renouncing all claim to authority over the subject matter, without particular reference to the party into whose hands it might come ; and thus in modern times the word has come to be used almost exclusively in the sense renunciation or desertion. [Hensleigh Wedgwood, "A Dictionary of English Etymology," 1859]

late 14c., "reduce in rank, etc.," from Old French abaissier "diminish, make lower in value or status; lower oneself" (12c.), literally "bend, lean down," from Vulgar Latin *ad bassiare "bring lower," from ad "to, toward" (see ad-) + Late Latin bassus "low, short" (see base (adj.)).

The form in English was altered 16c. by influence of base (adj.), making the word an exception to the rule that Old French verbs with stem -iss- enter English as -ish (comprehension might have played a role; earlier forms of abase often are identical with those of abash). Literal sense of "lower, depress" (late 15c.) is archaic or obsolete. Related: Abased; abasing.

"perplex or embarrass by suddenly exciting the conscience, discomfit, make ashamed," late 14c., abaishen, earlier "lose one's composure, be upset" (early 14c.), from Old French esbaiss-, present stem of esbaer "lose one's composure, be startled, be stunned."

Originally, to put to confusion from any strong emotion, whether of fear, of wonder, shame, or admiration, but restricted in modern times to effect of shame. [Hensleigh Wedgwood, "A Dictionary of English Etymology," 1859]

The first element is es "out" (from Latin ex; see ex-). The second may be ba(y)er "to be open, gape" (if the notion is "gaping with astonishment"), possibly ultimately imitative of opening the lips. Middle English Compendium also compares Old French abaissier "bow, diminish, lower oneself" (source of abase). Related: Abashed; abashing. Bashful is a 16c. derivative.

late 14c., "urge on, incite" (implied in abetting), from Old French abeter "to bait, to harass with dogs," literally "to cause to bite," from a- "to" (see ad-) + beter "to bait." This verb is probably from Frankish or some other Germanic source (perhaps Low Franconian betan "incite," or Old Norse beita "cause to bite"); ultimately from Proto-Germanic *baitjan, from PIE root *bheid- "to split," with derivatives in Germanic referring to biting. Sense of "encourage by aid or approval" is from 1779. Related: Abetted; abetting.

late 14c., "enduring, steadfast," present-participle adjective from abide (v.). Related: Abidingly.

late 14c., "state or condition of being able; capacity to do or act," from Old French ableté "ability (to inherit)," from Latin habilitatem (nominative habilitas, in Medieval Latin abilitas) "aptitude, ability," noun of quality from habilis "easy to manage, handy" (see able). One case where a Latin silent -h- failed to make a return in English (despite efforts of 16c.-17c. scholars); see H. Also in Middle English, "suitableness, fitness." Abilities "one's talents or mental endowments" is from 1580s.

"grammatical case denoting removal or separation," late 14c. as an adjective; mid-15c. as a noun (short for ablative case, originally in reference to Latin), from Old French ablatif and directly from Latin (casus) ablativus "(case) of removal," expressing direction from a place or time, coined by Julius Caesar from ablatus "taken away," past participle of auferre "to carry off or away, withdraw, remove," from ab "off, away" (see ab-) + the irregular verb ferre (past participle latum; see oblate) "to carry, to bear" (from PIE root *bher- (1) "to carry," also "to bear children"). The "from" case, the Latin case of adverbial relation, typically expressing removal or separation, also "source or place of an action." Related: Ablatival.