1. Not accessible to direct observation

See also: imperceptible, unperceivable

• enough
• enounce
• Enovid
• enplane
• enqueue
• enquire
• enquirer
• enquiringly
• enquiry
• enrage
• enraged
• enragement
• enrapt
• enrapture
• enraptured
• enrich
• enrichment
• Enrico Caruso
• Enrico Fermi
• enrobe
• enrol
• enroll
• enrollee
• enrollment
• enrolment