title (n.)

"small stroke or mark made by a pen-point in writing," late 14c., titil (Wycliffe, in Matthew v.18); it is title (n.) with a specialized sense (which developed in Late Latin and Romanic) and pronunciation. In Wycliffe it translates Latin apex in the Late Latin sense of "accent mark over a vowel," which itself translates Greek keraia (literally "a little horn"), used by the Greek grammarians of the accents and diacritical points. In this case the Greek word is a Biblical translation of Hebrew qots, literally "thorn, prick," used of the little lines and projections by which the Hebrew letters of similar form differ from one another.

Wycliffe's word is borrowed from a specialized sense of Latin titulus, which was used in Medieval Latin (and in Middle English and Old French) to indicate "a stroke over an abridged word to indicate letters missing" (compare Provençal titule "the dot over -i-", and tilde, which represents in English the Spanish form of the same word; also see iota).

As apex was used by the Latin grammarians for the accent or mark over a long vowel, titulus and apex became to some extent synonymous; hence Wyclif's use of titil, titel to render L. apex [OED]

As "smallest or very small part of something" by late 14c. (compare jot (n.)). The phrase to a tittle "with great exactness" is from c. 1600.

also intitle, late 14c., "to give a title to a chapter, book, etc.," from Anglo-French entitler, Old French entiteler "entitle, call" (Modern French intituler), from Late Latin intitulare "give a title or name to," from in- "in" (from PIE root *en "in") + titulus "title" (see title (n.)).

Meaning "to bestow (on a person) a rank or office" is mid-15c. Sense of "to give (someone) 'title' to an estate or property," hence to give that person a claim to possession or privilege, is mid-15c.; this now is used mostly in reference to circumstances and actions. Related: Entitled; entitling.