Definition of sel:
(n) :
A diminutive of the female given name Selena.
(n) :
(education, uncountable) Initialism of Social–emotional learning.
(n) :
(retail, countable) Initialism of shelf edge label.
(n) :
(computing) Initialism of single-event latchup (a destructive internal short circuit produced by a particle of ionizing radiation striking a CMOS computer chip).