Definition of rhotic:
(adj) :
(linguistics, of an English accent) That allows the phoneme /ɹ/ even when not followed by a vowel, as in bar (/bɑːɹ/) and bard or barred (/bɑːɹd/); (of an English speaker) who speaks with such an accent.
(adj) :
(linguistics, phonetics, of a phoneme) Having a sound quality associated with the letter R; having the sound of any of certain IPA symbols, including /ɹ/, /ɻ/, /ɚ/, /ɝ/ and /r/.
(n) :
(phonetics) A rhotic consonant or rhotic vowel (R-coloured vowel).