late 14c., excepcioun, "act or fact of leaving out or the excluding of" from the scope of some rule or condition, from Anglo-French excepcioun (late 13c. in a legal sense, "formal objection or protest entered by a defendant"), Old French excepcion, from Latin exceptionem (nominative exceptio) "an exception, restriction, limitation; an objection," noun of action from past-participle stem of excipere "to take out" (see except).

From c. 1400 as "a reservation or exemption;" from late 15c. as "something that is excepted."  The exception that proves the rule is from law: exceptio probat regulam in casibus non exceptis, "the exception proves the rule in cases not excepted;" exception here being "action of excepting" someone or something from the rule in question, not the person or thing that is excepted. The figure of speech in to take exception "find fault with, disapprove" is from excipere being used in Roman law as a modern attorney would say objection.

"liable to objection, that may be objected to, objectionable," 1660s (implied in exceptionableness), from exception (in the take exception to sense) + -able. Related: Exceptionably. Compare objectionable.

1828, "out of the ordinary course, forming an exception, unusual," from exception + -al (1). Related: Exceptionally. Exceptionalism "fact or quality of being exceptional" in some way, usually implying superiority to the unexceptional, is attested from 1864; the phrase American exceptionalism is attested by 1929, originally among communists, in reference to the argument about whether the United States is in some sense not subject to the historical rules of Marxism; it has been used in other ways since, often implying (and implicitly criticizing) a belief that the U.S. is somehow uniquely virtuous. Other noun forms include exceptionalness (1868), exceptionality (1851).

c. 1300, "to fasten (a gate, etc.) with a bar," from bar (n.1); sense of "to obstruct, prevent" is recorded by 1570s. Expression bar none "without exception" is recorded from 1866.

Old English butan, buton "unless; with the exception of; without, outside," from West Germanic *be-utan, a compound of *be- "by" (see by) + *utana "out, outside; from without," from ut "out" (see out (adv.)). Not used as a conjunction until late Old English, "on the contrary." Senses attested in early Middle English include "however, yet; no more than." As an introductory expression, early 13c. As a noun, "an objection, an exception" from late 14c.

Som man preiseth his neighebore by a wikked entente, foralwey he maketh a 'but' at the laste ende, that is digne of moore blame than worth is al the preisynge. [Chaucer, "Parson's Tale"]

word formed from the first letters of a series of words, 1943, American English coinage from acro- + -onym "name" (abstracted from homonym; ultimately from PIE root *no-men- "name"). With the exception of cabalistic esoterica and acrostic poetry, this way of forming words was exceedingly uncommon before 20c. For distinction of usage (regretfully ignored on this site), see initialism.

1560s, "in public," from public (adj.) + -ly (2). From 1580s as "by the public." Variant publically is attested by 1812, perhaps based on the fact that publicly is the only exception in this class of words, which as a rule are spelled -ically though often they are pronounced otherwise.

"of or pertaining to a midwife or midwifery," 1742, from Modern Latin obstetricus "pertaining to a midwife," from obstetrix (genitive obstetricis) "midwife," literally "one who stands opposite (the woman giving birth)," from obstare "stand opposite to" (see obstacle). The true adjective would be obstetricic, "but only pedantry would take exception to obstetric at this stage of its career" [Fowler]. Related: Obstetrical.

"a clause making what precedes conditional on what follows, a stipulation, a special exception to the general terms of a legislative act," mid-15c., from Medieval Latin proviso (quod) "provided (that)," the original Latin wording of the usual phrase at the beginning of clauses in legal documents (mid-14c.), from Latin proviso "it being provided," ablative neuter of provisus, past participle of providere (see provide). Related: Provisory.

c. 1400, exempcioun, "immunity from a law or statute, state of being free from some undesirable requirement," from Old French exemption, exencion or directly from Latin exemptionem (nominative exemptio) "a taking out, removing," noun of action from past-participle stem of eximere "remove, take out, take away; free, release, deliver, make an exception of," from ex "out" (see ex-) + emere "buy," originally "take," from PIE root *em- "to take, distribute."