las·so (lās'ō, lā-sōō') n.
pl.las·sos or las·soes A long rope with a running noose at one end, used especially to catch horses and cattle. Also called lariat. tr.v.
las·soed, las·so·ing, las·sos or las·soes To catch with or as if with such a long rope.
[Spanish lazo, from Vulgar Latin *laceum, noose; see lace.] las'so·er n.