1. Not yet discovered
   - undiscovered

See also: unknown

• strong belief
• strong breeze
• strong drink
• strong force
• strong gale
• four-in-hand
• four-lane
• four-leaf
• four-leaved
• four-letter Anglo-Saxon word
• four-letter word
• four-lined leaf bug
• four-lined plant bug
• four-lobed
• four-membered
• four-minute man
• four-needled
• four-o'clock family
• four-part harmony
• four-party
• four-petaled
• four-petalled
• four-ply
• four-poster
• four-pounder