There are 38 5-letter words that start with 'ab'.
Note: These 38 5-letter words that start with 'ab' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with abs, abo, aba, abr, abe, abl, abd, abu, abb, abi, abn, abj, abh, aby, abc, abf, abm, abv, abw.
3-letter words start with 'ab' (4)