sentence

c.1290, "doctrine, authoritative teaching," from O.Fr. sentence (12c.), from L. sententia "thought, meaning, judgment, opinion," from sentientem, prp. of sentire "be of opinion, feel, perceive" (see sense).
Loss of first -i- in L. by dissimilation. Meaning "punishment imposed by a court" is from c.1300; that of "grammatically complete statement" is attested from 1447, from notion of "meaning," then "meaning expressed in words."
http://www.etymonline.com/index.php?term=sense

sense (n.)
c.1400, "faculty of perception," also "meaning or interpretation" (esp. of Holy Scripture), from O.Fr. sens, from L. sensus "perception, feeling, undertaking, meaning," from sentire "perceive, feel, know," prob. a fig. use of a lit. meaning "to find one's way," from PIE base *sent- "to go" (cf. O.H.G. sinnan "to go, travel, strive after, have in mind, perceive," Ger. Sinn "sense, mind," O.E. sið "way, journey," O.Ir. set, Welsh hynt "way"). Application to any one of the external or outward senses (touch, sight, hearing, etc.) first recorded 1526.