Longman Dictionary of Contemporary English
castor sugar
noun
EXAMPLES FROM CORPUS
▪ Two tomatoes cut in half and sprinkled with a little castor sugar.
Wiktionary
castor sugar
n. (context UK NZ English) Alternative form of '''caster sugar'''.
WordNet
castor sugar
n. very finely granulated sugar that was formerly sprinkled from a castor [syn: caster sugar]