1. Of or relating to a geological eon (longer than an era)
   - aeonian 
2. Continuing forever or indefinitely
   - ageless, aeonian, eternal, everlasting, perpetual, unending, unceasing

See also: eon, lasting, permanent

• highborn
• 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