There are 19 words that start with 'watt'.
| watt | watts | watter |
| wattle | wattage | wattape |
| wattest | wattled | wattles |
| wattages | wattapes | watthour |
| wattless | wattling | watthours |
| wattmeter | wattlebird | wattmeters |
| wattlebirds | ||
Note: These 19 words that start with 'watt' are found from the USA & Canada version of the tournament Scrabble word list.