plait vs pigtail

plait and pigtail both are nouns.

Word	Noun	Adjective	Verb	Adverb
plait	Yes	No	Yes	No
pigtail	Yes	No	No	No

As nouns, pigtail is a hyponym of plait; that is, pigtail is a word with a more specific, narrower meaning than plait:

Other hyponyms of plait include queue.

plait (noun)	pigtail (noun)
any of various types of fold formed by doubling fabric back upon itself and then pressing or stitching into shape	a plait of braided hair
a hairdo formed by braiding or twisting the hair

plait (verb)	pigtail (verb)
weave into plaits
make by braiding or interlacing