Al-Saghir

The word

Lisān al-ʿArab gives al-ṣighar as the opposite of largeness and keeps apart two senses that a single English word runs together: ṣighar al-jirm, smallness in bulk or body, and ṣighar al-sinn, fewness of years. Al-aṣghar is the comparative, and the lexicon most often gives it in a pair with al-akbar, where the two are not being measured against a standard but told apart from each other.

The younger of two men of one name

That pairing is what the word usually does in a name. Arab naming returns the same given names through a household in a short cycle — a boy is called after his grandfather or his uncle, often while that man is living — and a house then holds two Muḥammads or two ʿAlīs at once. They are separated in speech and in writing as al-kabīr and al-ṣaghīr, the elder and the younger. The word is doing bookkeeping, not description: it says which of the two is meant, and reports nothing about anyone's size. Where the distinction held for a generation or more, the descendants of the younger man could carry it forward, and al-Ṣaghīr became the name of that branch of the family.

Bearing the name

A family name of this kind records a byname that was applied to one ancestor and then stayed with his descendants. It reports how he was called, not a lineage, and it says nothing about the body, the character or the standing of anyone who bears it now. It attaches to no tribe, and two families bearing it need have no connection to one another beyond the word itself.