spyhole
Small door aperture
A spyhole is a small hole through which to observe without being seen.
Most commonly, it's the peephole in a door that lets you see who's outside before opening: She checked the spyhole before unlocking the door.
The term applies to any small opening used for covert observation.
Adjustable optical inlet
Small lens showing visitors
- doorbellEntry alert device
- intercomShort-range voice transmitter
- chain lockLinked metal door restraint
- deadboltKey-operated door lock
Ongoing observation of something
- reconnaissanceInformation-gathering before action
- undercoverSecretly engaged in espionage
- covertIntentionally concealed
- observationAttentive watching or remark
watching · stakeout · infiltration · counterintelligence · intelligence · eavesdropping · informant · sleuth
Fleeting view
- peekFurtive brief look
- peerOne of similar standing
- lookDirect one's gaze
- observePerceive with attention
watch · scrutinize · inspect · survey · sight · one-way · fish-eye · wide-angle
Freedom from harm
- protectionGuarding against harm
- screeningEvaluative selection process
- verificationProving something accurate
- precautionPreventive safety measure
vigilance · awareness · stranger · intruder · home security · identification · caution
aperture
Adjustable optical inlet
door viewer
Small lens showing visitors
- doorbellEntry alert device
- intercomShort-range voice transmitter
- chain lockLinked metal door restraint
deadbolt · knocker · threshold · entry · front door · visitor · caller
monitoring
Ongoing observation of something
- reconnaissanceInformation-gathering before action
- undercoverSecretly engaged in espionage
- covertIntentionally concealed
observation · watching · stakeout · infiltration · counterintelligence · intelligence · eavesdropping · informant · sleuth · detective
glimpse
Fleeting view
observe · watch · scrutinize · inspect · survey · sight · one-way · fish-eye · wide-angle · distortion
safety
Freedom from harm
- protectionGuarding against harm
- screeningEvaluative selection process
- verificationProving something accurate
precaution · vigilance · awareness · stranger · intruder · home security · identification · caution
spyholepicture window
Large undivided window
glass wall · bay window · French doors · curtain wall · display window
spyholetwo-way mirror
Selectively transparent reflective pane
clear glass · open door · window · welcome mat · reception area
spyholeobservation deck
Elevated platform for sightseeing
two-way mirror · glass partition · open window · face-to-face meeting