1. Designed to activate or move or regulate itself
   "a self-activating sprinkler system"
   - self-acting, self-moving, self-regulating

See also: automatic

• ontogenesis
• ontogenetic
• ontogeny
• ontological
• ontologically
• ontologist
• ontology
• onus
• onward
• onward motion
• onwards
• onya
• onycha
• Onychium
• Onychogalea
• onycholysis
• Onychomys
• Onychophora
• onychophoran
• onychosis
• onymous
• onyx
• onyx marble
• onyxis
• oocyte