1. Very occasionally

Encyclopedia: Once in a blue moon

• highboy
• highbrow
• highbrowed
• highbush cranberry
• highchair
• higher
• higher cognitive process
• higher criticism
• higher education
• higher law
• Higher National Diploma
• higher rank
• higher status
• higher-ranking
• higher-up
• highest common factor
• highfalutin
• highfaluting
• highflier
• highflyer
• highflying
• highjack
• highjacker
• highjacking
• highland