noun
main sequence
In astronomy, the band on the Hertzsprung–Russell diagram where most stars lie, fusing hydrogen in their cores.
太陽は主系列星の一つです。
The Sun is a main-sequence star.
noun
principal series
In physics and mathematics, a principal series representation or related concept; a technical term used in group theory and spectral analysis.
この群の主系列表現について研究している。
I am researching the principal series representations of this group.