tīˈlōsə̇s noun
( plural tylo·ses -ōˌsēz)
Etymology: New Latin, from Greek tylōsis act of making or becoming callous, from tyloun to make callous, make knobby, from tylos callus, knob — more at thole
1. : one of the protrusions from plant parenchyma cells into adjacent tracheary elements usually through a pit-pair and often numerous enough to completely fill the lumen
2. : a thickening and hardening of an organ or body part : callosity