geminate
Concise Oxford English Dictionary © 2008 Oxford University Press:
geminate Phonetics
▶adjective /ˈdʒɛmɪneɪt, -nət/ consisting of identical adjacent speech sounds; doubled. ▶verb /ˈdʒɛmɪneɪt/ double or repeat (a speech sound).
– derivatives
gemination noun.
gemination noun.
– origin ME (in sense ‘duplicate, doubled’): from L. geminat-, geminare ‘double, pair with’, from geminus ‘twin’.
'geminate' also found in these Oxford entries:

