secpar vs astronomy unit

secpar and astronomy unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
secpar	Yes	No	No	No
astronomy unit	Yes	No	No	No

As nouns, astronomy unit is a hypernym of secpar; that is, astronomy unit is a word with a broader meaning than secpar:

secpar: a unit of astronomical length based on the distance from Earth at which stellar parallax is 1 second of arc; equivalent to 3.262 light years
astronomy unit: a linear unit used for astronomical distances

secpar (noun)	astronomy unit (noun)
a unit of astronomical length based on the distance from Earth at which stellar parallax is 1 second of arc; equivalent to 3.262 light years	a linear unit used for astronomical distances