Tsarevich
Tsarevich (Russian:Царе́вич, IPA: [tsɐˈrʲevʲɪtɕ]) is a Slavic title given to tsars' sons. Under the 1797 Pauline house law, the title was discontinued and replaced with Tsesarevich for the heir apparent alone. His younger brothers were called Grand Dukes. English sources often confused the two terms.