intestinus

Etymology
The first element from (so De Vaan 2008) or  (so WH 1938), both from  - cf. ,, ; the second element represents a compound with (🇨🇬): zero-grade extended by -i-, or e-grade with later remodelling after  (so De Vaan); or is a chaining of the suffixes  and  (so WH). Compare, without the middle element.

Adjective

 * 1) internal in various senses, namely:
 * 2)  civic, domestic, internal
 * 3)  individual, personal, private
 * 4)  internal, inward
 * 5) ( ~um) the Mediterranean Sea
 * 6) ( ~um)  interior woodwork, joinery