per·fo·rin 
(pûrfər-ĭn)
(pûrfər-ĭn)n.
A protein released by natural killer cells and cytotoxic T lymphocytes that causes lysis of target cells by forming pores in their membranes.
[PERFOR(ATE) + -IN.]
- ground-fault interrupter
- groundfish
- ground floor
- ground glass
- ground hemlock
- groundhog
- ground hog
- Groundhog Day
- ground ivy
- groundkeeper
- groundkeeper
- groundless
- groundlessly
- groundlessness
- ground level
- groundling
- ground loop
- groundmass
- ground meristem
- groundnut
- ground out
- groundout
- ground pine
- ground plan
- ground plum