825 Tanina (prov. designation: or ) is a stony background asteroid from the region of the Flora family, located in the inner part of the asteroid belt. It was discovered on 27 March 1916, by Russian astronomer Grigory Neujmin at the Simeiz Observatory on Crimea. The elongated S-type asteroid (SR) has a rotation period of 6.9 hours and measures approximately in diameter. Any reference of the asteroid's name to a person is unknown. Orbit and classification Tanina is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method (HCM) by Nesvorný to its proper orbital elements. In the 1995 HCM-analysis by Zappalà, however, Tanina is a member of the Flora family (), a giant asteroid family and the largest family of stony asteroids in the main-belt. In the HCM-analysis by Milani and Knežević (AstDys), it is also a background asteroid as this analysis does not recognize the Flora asteroid clan. The asteroid orbits the Sun in the inner main-belt at a distance of 2.1–2.4 AU once every 3 years and 4 months (1,213 days; semi-major axis of 2.23 AU). Its orbit has an eccentricity of 0.08 and an inclination of 3° with respect to the ecliptic. Discovery Tanina was discovered by Russian astronomer Grigory Neujmin at the Simeiz Observatory on Crimean peninsula on 27 March 1916. One week later, on 3 April 1916, it was independently discovered by Max Wolf at the Heidelberg Observatory in Germany. The Minor Planet Center only recognizes the first discoverer. The asteroid was first observed as at Heidelberg on 17 October 1904, while the body's observation arc begins with Wolf's independent discovery observation. Naming This minor planet was named "Tanina". Any reference of its name to a person or occurrence is unknown. Unknown meaning Among the many thousands of named minor planets, Tanina is one of 120 asteroids for which has been published. All of these asteroids have low numbers, the first one being . The last asteroid with a name of unknown meaning is . They were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth. Physical characteristics In the Tholen classification, Tanina is closest to a stony S-type asteroid, and somewhat similar to an uncommon R-type asteroid, while in the SMASS classification by Bus–Binzel, Tanina is a common S-type asteroid. Rotation period In February 2002, a rotational lightcurve of