Why is the ninth month called September?
late 14c., "full of pores," from Old French poros (14c., Modern French poreux), from Medieval Latin porosus; or directly from Latin porus "an opening" (see pore (n.)). Figurative use from 1640s.
porous po·rous (pôr'əs)adj.
Full of or having pores.
Admitting the passage of gas or liquid through pores.