OTMA was an acronym sometimes used by the four daughters of Emperor Nicholas II of Russia and his consort, Alexandra Feodorovna, as a group nickname for themselves, built from the first letter of each girl's name in the order of their births:
- Ольга – Olga Nikolaevna Romanova (15 November 1895 – 17 July 1918) was the eldest daughter.
- Татьяна – Tatiana Nikolaevna Romanova (10 June 1897 – 17 July 1918) was the second child.
- Мария – Maria Nikolaevna Romanova (26 June 1899 – 17 July 1918) was the third and middle child.
- Анастасия – Anastasia Nikolaevna Romanova (18 June 1901 – 17 July 1918) was the fourth and youngest daughter.
In childhood the grand duchesses came up with ОТМА as a sign of sibling closeness and affection for one another, writing it in their diaries. The girls were great granddaughters of Queen Victoria and, although "thoroughly Russian," grew up speaking both Russian and English fluently among themselves. Whilst the family was in captivity after the Russian Revolution of 1917 they were allowed to send few letters so the sisters often signed this nickname on cards they had written together for loved ones and friends.
- alexanderpalace.org, The Grand Duchesses – OTMA, retrieved 14 June 2009