Why is the ninth month called September?
1728, "secreting sebum," from Latin sebaceus "of tallow," from sebum "tallow, grease" (see sebum). Meaning "oily, greasy, fatty" is from 1783.
sebaceous se·ba·ceous (sĭ-bā'shəs)adj.
Of, resembling, or characterized by fat or sebum; fatty.
Secreting or producing fat or sebum.