Having the nature of essence; not physical.
Necessary.
Necessary for survival but not synthesized by the organism, thus needing to be ingested.
Being in the basic form; showing its essence.
Really existing; existent.
Very important; of high importance.
Such that each complementary region is irreducible, the boundary of each complementary region is incompressible by disks and monogons in the complementary region, and no leaf is a sphere or a torus bounding a solid torus in the manifold.
Idiopathic.
A necessary ingredient.
A fundamental ingredient.
To the lowest degree.
The smallest amount.
He always tries to get away with doing the minimum.
The lowest limit.
A period of minimum brightness or energy intensity (of a star).
The smallest member of a batch or sample or the lower bound of a probability distribution.
A lower bound of a set which is also an element of that set.