Crimson

Crimson was a colour.

The War Doctor wore a crimson scarf. (COMIC: Ambush)

Ace wore a crimson t-shirt with a v-neck collar. (TV: Survival)

Silurian commanders wore crimson vests. (TV: Cold Blood; GAME: The Eternity Clock)

In the 20th century, Torchwood Three found a deep-lavender emotional amplifier. It pulsed crimson when it detected anger, amplifying it into rage. (PROSE: Slow Decay)