Other forms: detected, detecting, detects
To detect something is to notice it when it is faint, hidden, or trying not to be noticed. A smoke alarm detects smoke before your nose does, a blood test detects an infection, and you detect a slight coolness in someone's voice.
The family around it is large and useful: detection, detector, detective, detectable, undetected. The word leans towards instruments and evidence, so it turns up in the passive constantly — 'the leak was detected on Tuesday', 'no fault was detected'. What you detect is already there; you pick up a signal, you do not decide one. That is the difference from notice, which is casual, and from discover, which is bigger news. In conversation people say 'I could tell', and detect stays behind for reports, doctors and machines.
1verbdetectTo discover that something is present, especially something faint or hidden.
“The scanner detected a crack in the wing.”
2verbnoticeTo notice a quality or feeling that is barely showing.
“I detected a note of impatience in his reply.”
Also accepted in games: sense
Detect comes from Latin detegere, 'to uncover' — de-, off, plus tegere, 'to cover'. To detect a thing was to take the roof off it and look inside. That same tegere lies under tile, thatch and tegument, all of them coverings; detect is the one that removes them.
Proto-Indo-European
*(s)teg- (cover)
Latin
detectus
English, today
detect
Built from
From Latin detectus, perfect passive participle of detegere (“to uncover or disclose”), from de- + tegere (“to cover”); see tegument, tile, thatch. Sense "to work or solve cases as a detective" a back-formation from detective.
Etymology from Wiktionary, CC BY-SA