The phrase "a principal part" is correct and usable in written English.
It can be used to refer to a major or significant component of something, often in contexts like education, music, or any structured system.
Example: "In the play, she was cast in a principal part, showcasing her talent and dedication to the role."
Alternatives: "a key role" or "a major component".
The Liber Judiciorum was a principal part of the Visigothic legacy received by medieval Spain.
When she didn't get a principal part, "It just crushed me," she said.
A new generation of anthropologists came to see activism on their subjects' behalf as a principal part of the job.
Chicago, for better or worse, is a principal part of the McCain campaign's effort to bring Mr Obama down.Chicago itself remains the centre of efforts to lift him up.
1292 August 23, 1358 Isabella Of France, (born 1292 died Aug. 23, 1358) queen consort of Edward II of England, who played a principal part in the deposition of the King in 1327.
COPELAND I really felt like I was going to crack when I went through probably three or four years of trying to pace myself in doing a full corps schedule on top of soloist and sometimes a principal part.
The paper is devoted to a study of the null controllability for the semilinear parabolic equation with a complex principal part.
On the other hand, if we write 'Socrates and a donkey', the phrase is common because it contains a common term as an equally principal part.
Applying ℒ to both parts of (2.4), we obtain the decomposition L x = Q δ x + A r x, (7) where Q = L Λ : B → B is the principal part, and A = L Y : R n → B is the finite-dimensional part of ℒ.
The third principal part is a distinct indicative imperfective stem (Geʿez yə-qabbər) that employs the same prefixes and circumfixes as the modal verb form but has a distinctive disyllabic shape (-CaC[C]əC-).
Note that the principal part of a corresponding differential operator is non self-adjoint.
