Letters that make opal
a, o, l, p are letters that make 'opal'
nopal, opals, copal are words created by adding a letter to 'opal'
1 possible definitions for 'opal'
Under this definition, opal is a noun and has the following properties:
'opal' can be a type of mineral, opaque gem.
black opal, fire opal, girasol, harlequin opal are types of 'opal'.