The desire to know, learn, or investigate.
The desire to know, learn, or investigate — the pull toward the unknown.
Specifically the desire to know or resolve a gap in understanding, goal-directed toward acquiring knowledge — where interest is broad, mild engagement and fascination is intense absorption. Overlaps intrigue, but intrigue is curiosity piqued by something mysterious, whereas curiosity can attach to anything one wants to know. Oriented to present unknowns rather than future outcomes (unlike hope or anticipation). Can be a momentary state or a stable trait; note the mildly negative “nosiness” subsense.
From Latin cura “care” → curiosus “inquiring eagerly, meddlesome” → curiositas “desire of knowledge.” Entered English late 14c., often in bad senses (“prying; vain interest”).
A shift in evaluative tone: in Middle English it commonly meant prying or vain interest; the neutral-to-positive “desire to learn what is unknown” emerged in the early 17th century. The concrete sense “a rare or strange object” is from the 1640s (giving “curiosity-shop”). No reliable recent-generation shift.