From The Collaborative International Dictionary of English v.0.48 :
Sens \Sens\, adv. [See Since.]
Since. [Obs.] --Spenser.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
sens
n 1: street names for marijuana [syn: pot, grass, green
goddess, dope, weed, gage, sess, sens, smoke,
skunk, locoweed, Mary Jane]