There are 13 words that start with 'euca'.
| eucaine | eucaines | eucalypt | 
| eucalypti | eucalypts | eucaryote | 
| eucalyptol | eucalyptus | eucaryotes | 
| eucalyptole | eucalyptols | eucalyptoles | 
| eucalyptuses | ||
Note: These 13 words that start with 'euca' are found from the USA & Canada version of the tournament Scrabble word list.