Knit cap
A whale hunter wearing a knit cap
Spock wearing a Starfleet knit cap
Spock wearing a knit cap in 1930
A knit cap, toque, or beanie was a piece of knitted headwear worn in cold weather.
Time-traveler Spock wore a knit cap to disguise his Vulcan features in 1930 New York City, Earth. (TOS: "The City on the Edge of Forever")
After a Vulcan ship crash landed in Carbon Creek on Earth in 1957, Mestral wore a knit cap to disguise his Vulcan ears. (ENT: "Carbon Creek")
Some of the whale hunters on the Bering Sea who nearly harpooned George and Gracie in 1986 wore knit caps. (Star Trek IV: The Voyage Home)
In 2022, an individual walking by The Lakeview wore a Toronto Maple Leafs beanie. (SNW: "Tomorrow and Tomorrow and Tomorrow")
After Spock was temporarily made fully Human by the Kerkhovians in 2259, he wore a regulation knit cap with Starfleet insignia to disguise his Human ears from his mother. (SNW: "Charades")
In 2268, Spock disguised his Vulcan ears with a knit cap on planet 892-IV, given to him by Septimus' group of runaway slaves. However, a police officer took off his hat and realized Spock is "a barbarian". (TOS: "Bread and Circuses")
In the same year, Spock again disguised his Vulcan features by wearing a knit cap when he beamed down to planet Ekos. (TOS: "Patterns of Force")