There are 9 13-letter words that start with 'coc'.
| cocainization | cocarboxylase | 
| cocarcinogens | cochairperson | 
| cockfightings | coconspirator | 
| cocounselling | cocultivating | 
| cocultivation | |
Note: These 9 13-letter words that start with 'coc' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with cock, coco, coca, coch, cocc, cocu, cocr, coci.
4-letter words start with 'coc' (3)