Is “Instar” a Scrabble word?
Yes
INSTAR
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Instar
/ˈɪnstɑː/
noun
1.Any one of the several stages of postembryonic development which an arthropod undergoes, between molts, before it reaches sexual maturity.
2.An arthropod at a specified one of these stages of development.
3.(by extension) A stage in development.