noun
molecule
Chemistry term for a molecule, often used with substance names such as 水の分子 or in compounds such as 分子構造.
水の分子は、水素原子二つと酸素原子一つからできている。
A water molecule is made of two hydrogen atoms and one oxygen atom.
noun
numerator
Mathematical term for the number or expression above the line in a fraction; contrasted with 分母.
三分の二では、二が分子で三が分母です。
In two thirds, two is the numerator and three is the denominator.
noun
element of a group; member
Used for a person or element within a group, especially in set phrases or evaluative compounds such as 不穏分子 or 危険分子. It is not the ordinary everyday word for a group member.
警察は組織内の不穏分子を警戒していた。
The police were watching out for subversive elements within the organization.
noun
Rare or limited use meaning a small particle; do not confuse this with the grammar term 助詞. In ordinary modern technical contexts, 粒子 is usually clearer unless 分子 specifically means molecule.
See also: 微分子
文脈によっては、分子が小さな粒子を指すことがある。
Depending on the context, 分子 can refer to a small particle.