caster sugar or castor sugarnoun

• officer of arms
• official
• officialese
• officialism
• Official Receiver
• official secret
• officiant
• officiate
• officinal
• officious
• offie
• offing
• offish
• off-key
• off-label
• off-licence
• off limits
• off-line
• off-load
• off-message
• off one's chump
• off one's head
• off one's own bat
• off one's rocker
• off one's stroke