Upvote:2
I assume that you are asking about Latin, not about English.
praesidens, genitive praesidentis is the present active participle of the verb praesideo “to sit in front of”, and then “to preside over”. For the substantivised participle praesidens the Latin dictionary by Lewis and Short has a citation from Tacitus where “superbia praesidentium” has the meaning “governors”. A more common term in classical Latin is the noun praeses, genitive praesidis, from the same root and preverb. It occurs in the meaning “one that presides over, a president, superintendent, head, chief, ruler” at the latest from the time of Virgil onwards.
Upvote:7
From the Online Etymology Dictionary entry the Latin is given as praesidentum (nominative praesidens) meaning "president, governor", from whence English derived it via the Old French "president".
The OED lists several usages dating from the 1370's and 1380's for both the appointed head of a territory or district (sense 1) and for the appointed or elected head of a committee or group who then presides over meetings (sense 2).
The 1374 entry in the OED (sense 1) is the oldest I saw there.