[3][4] The crowned woodnymph was formally described in 1843 by the French ornithologist Jules Bourcier from a specimen collected in Colombia.

Adult males of the nominate subspecies T. c. colombica have a violet forehead, crown, upper back, and belly.

Immature males have dusky crown, throat, and underparts with very limited iridescent purple feathers.

[8] Males of subspecies T. c. townsendi have a bronze nape and a green belly with violet on the sides.

T. c. venusta males are larger than the nominate with a longer tail and have a very dark blue-green nape.

[8] T. c. fannyae males replace the nominate's violet forehead and crown with glittering green but are otherwise very similar.

Males of T. c. hypochlora have a mostly green belly with a little violet, a blue nape and sides of the breast, and white fringes on the undertail coverts.

Both sexes defend rich nectar sources, but studies have shown territorial differences between them.

Females' territories also received more intruders than males, and produced higher mean nectar volume.

The nest is a cup of treefern scales and plant down bound with spiderweb, with lichen and moss on the outside.

Much of its habitat in Central America and northern Colombia has been deforested, but it appears to be able to use fragmented forest.