|1.||[ adjective ] (biology) belonging to or active during the night|
"nocturnal animals are active at night" "nocturnal plants have flowers that open at night and close by day"
|Related terms:||diurnal biology nighttime|
|2.||[ adjective ] of or relating to or occurring in the night|
|3.||[ adjective ] of or during or relating to the night|
"a nocturnal journey" "nocturnal stillness" "nocturnal predators"