There are 8 words that start with 'isobu'.
| isobutyl | isobutane | isobutene |
| isobutyls | isobutanes | isobutenes |
| isobutylene | isobutylenes | |
Note: These 8 words that start with 'isobu' are found from the USA & Canada version of the tournament Scrabble word list.