barring (n.)youdaoicibaDictYouDict[barring 词源字典]
late 14c., "act of fastening with a bar," verbal noun from bar (v.). Meaning "exclusion" is from 1630s. As a preposition, "excepting, excluding," it is from late 15c. Schoolhouse prank of barring out the teacher was in use before 1728.[barring etymology, barring origin, 英语词源]
except (v.)youdaoicibaDictYouDict
late 14c., "to receive," from Middle French excepter (12c.), from Latin exceptus, past participle of excipere "to take out, withdraw; make an exception, reserve," from ex- "out" (see ex-) + capere "to take" (see capable). Meaning "to leave out" is from 1510s. Related: Excepted; excepting. Adjectival function led to use as a preposition, conjunction (late 14c.).
exception (n.)youdaoicibaDictYouDict
late 14c., from Anglo-French excepcioun, 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).

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 is from excipere being used in Roman law as a modern attorney would say objection.
isolate (v.)youdaoicibaDictYouDict
by 1786, a new formation from isolated (q.v.).
The translation of this work is well performed, excepting that fault from which few translations are wholly exempt, and which is daily tending to corrupt our language, the adoption of French expressions. We have here evasion for escape, twice or more times repeated; brigands very frequently; we have the unnecessary and foolish word isolate; and, if we mistake not, paralize, which at least has crept in through a similar channel. Translators cannot be too careful on this point, as it is a temptation to which they are constantly exposed. ["The British Critic," April 1799]
As a noun from 1890, from earlier adjectival use (1819).
theyoudaoicibaDictYouDict
definite article, late Old English þe, nominative masculine form of the demonstrative pronoun and adjective. After c.950, it replaced earlier se (masc.), seo (fem.), þæt (neuter), and probably represents se altered by the th- form which was used in all the masculine oblique cases (see below).

Masc. Fem. Neut. Plural
Nom. se seo þæt þa
Acc. þone þa þæt þa
Gen. þæs þære þæs þara
Dat. þæm þære þæm þæm
Inst. þy, þon -- þy, þon --


Old English se is from PIE root *so- "this, that" (cognates: Sanskrit sa, Avestan ha, Greek ho, he "the," Irish and Gaelic so "this"). For the þ- forms, see that. The s- forms were entirely superseded in English by mid-13c., excepting a slightly longer dialectal survival in Kent. Old English used 10 different words for "the" (see table), but did not distinguish "the" from "that." That survived for a time as a definite article before vowels (that one or that other).

Adverbial use in the more the merrier, the sooner the better, etc. is a relic of Old English þy, the instrumentive case of the neuter demonstrative (see that).