Tender
Middle English: from Old French tendre, from Latin tener ‘tender, delicate’.
wiktionary
From Middle English tender, tendere, from Anglo-Norman tender, Old French tendre, from Latin tener, tenerum(“soft, delicate”).
From Middle English tender, tendur, tendir, tendre, from the adjective (see above).
From Middle English tendren, from the adjective (see above).
From tend + -er.
From Middle English tendren, from Old French tendre(“stretch out”).
etymonline
tender (adj.)
"soft, easily injured," early 13c., from Old French tendre "soft, delicate; young" (11c.), from Latin tenerem (nominative tener) "soft, delicate; of tender age, youthful," from a derivative of PIE root *ten- "to stretch," on the notion of "stretched," hence "thin," hence "weak" or "young." Compare Sanskrit tarunah "young, tender," Greek teren "tender, delicate," Armenian t'arm "young, fresh, green."
Meaning "kind, affectionate, loving" first recorded early 14c. Meaning "having the delicacy of youth, immature" is attested in English from early 14c. Related: Tenderly; tenderness. Tender-hearted first recorded 1530s.
tender (v.)
"to offer formally," 1540s, from French tendre "to offer, hold forth" (11c.), from Latin tendere "to stretch, extend," from PIE root *ten- "to stretch." The retention of the ending of the French infinitive is unusual (see render (v.) for another example).
tender (n.1)
"person who tends another," late 15c., probably an agent noun formed from Middle English tenden "attend to" (see tend (v.2)); later extended to locomotive engineers (1825) and barmen (1883). The meaning "small boat used to attend larger ones" first recorded 1670s.
tender (n.2)
"formal offer for acceptance," 1540s, from tender (v.). Specific sense of "money offered as payment" is from 1740, in legal tender "currency which by law must be accepted from a debtor" (see legal).
