milt (n.) Look up milt at Dictionary.com
Old English milte "spleen," from Proto-Germanic *miltjo- (source also of Old Frisian milte, Middle Dutch milte, Dutch milt "spleen, milt of fish," Old High German milzi, German milz, Old Norse milti), possibly from PIE root *mel- (1) "soft" (see mild). Meaning "fish sperm" is late 15c.