Robin
A pet form of Robert, originally a familiar nickname that later became a surname in its own right.
The #6,510 most common surname in the United States (2010 Census) — about 1 in every 59,237 Americans shares it.
Etymology
Robin began as a medieval diminutive of Robert, with the familiar -in ending used to make a shorter, affectionate form. In French and English usage it could function as an everyday nickname rather than a formal given name. The surname therefore means, in effect, “son of Robert” or “descendant of someone called Robin.”
History
The name is well known from Middle English and Anglo-French records, and it appears in literary sources such as Chaucer and Piers Plowman as a plain personal name. It also became familiar through Robin Hood tradition, though the surname itself is older and independent of the outlaw legend. In some cases related surnames and spellings developed from the same nickname, including forms like Robyn and Robinson-related variants in wider surname history.
Origin
Regions
Variant spellings
Fun fact
Medieval writers could use Robin almost like a social label: one cited example contrasts “Robert” as a gentleman with “Robin” as a poorer man.
From the historical record
“ROBIN, a double dim. of Robert, q.v. [Fr. Robin\ John 'Rohia.— Hund. Rolls. Til Robyn the ropere Arobs bi the southe. — Piers Plowman, 3147-8. Now am I Robert [i.e. a gentleman], now Robyn [i.e. a poor man]. — Chaucer, Rom. of the Rose, 6337.”
— Surnames of the United Kingdom: a concise etymological dictionary (2 vols in 1)