-baş / -başı

Kocabaş and Onbaşı end in the same word but do not describe the same thing. The first names an appearance, the second an office. The difference comes down to one sound, the final -ı.

Baş ‘head’ is a full word and does not change under vowel harmony. In surnames it occurs in two structures. In the first, baş stays bare and the adjective before it describes it: koca baş ‘big head’, kara baş ‘black head’. In the second, baş takes the third-person possessive and becomes başı: on başı, yüz başı. This is a noun compound meaning ‘the head, the leader of something’. The ending does not vary after a vowel, because baş itself ends in a consonant.

The first structure usually describes the body or a temperament. Kocabaş is ‘big-headed’, Karabaş ‘black-headed’. Akbaş means ‘white-headed, white-haired’, and Delibaş ‘wild-headed, fearless’. Such nicknames are explained calmly. They do not suggest that any family had the trait; they only give the meaning of the word. Erbaş stands slightly apart: the dictionary lists it as the general term for the ranks of corporal and sergeant.

The second structure names the head of a group. Onbaşı is ‘head of ten’, a corporal, and Yüzbaşı ‘head of a hundred’, a captain. Bölükbaşı commands a company. Yiğitbaşı analyses as ‘head of the brave’. Subaşı was an office in the Ottoman period. Its first element is usually explained as Old Turkic sü ‘army’. Linking it with modern su ‘water’ is a popular explanation. On the site these forms go to the military ranks or the Ottoman titles. They can also take -oğlu, as in Bölükbaşıoğlu.

The 1934 rules bear directly on these words. Article 3 of the Surname Law bans names of rank and public office as surnames. Article 9 of the Surname Regulation likewise lists ranks and offices of the old and new state cadres. Even so, forms such as Onbaşı and Yüzbaşı appear in today’s registers. This page describes only the forms and their meanings.

The best-known false friend is Demirbaş. The dictionary gives it as a single word meaning ‘fixture, an item an institution keeps in permanent use’. It is not read as demir plus baş. As a surname, too, it is treated with that dictionary meaning.

In short, with a surname in -baş, look first for the final -ı. Without it, the name usually describes an appearance. With it, the name is most likely an office or a rank.