um·bil·i·cus 
(ŭm-bĭlĭ-kəs, ŭm′bə-līkəs)
(ŭm-bĭlĭ-kəs, ŭm′bə-līkəs)n. pl. um·bil·i·ci (-sī′)
1. See navel.
2. Biology A small opening or depression similar to a navel, as the hollow at the base of the shell of some gastropod mollusks, one of the openings in the shaft of a feather, or the hilum of a seed.
[Latin umbilīcus; see nobh- in the Appendix of Indo-European roots.]
- secondary structure
- secondary succession
- secondary syphilis
- secondary tissue
- second banana
- second base
- second baseman
- second best
- second-best
- second blessing
- second childhood
- second class
- second-class
- second class
- Second Coming
- second cousin
- second-degree burn
- Second Empire
- second fiddle
- second-generation
- second growth
- second-guess
- second-guesser
- second hand
- second hand