Tse (Ц, ц) is a letter in the Cyrillic alphabet. It looks somewhat like U with square corners and a "pig tail" on the bottom right. It is pronounced /ts/, like the ts in "cats".
It is the 23rd letter of the Russian alphabet, and is thought to have come from the Hebrew letter Tsadi (צ), via the Glagolitic letter Tsi: 
Usage in Russian
It is used both in native Slavic words, as a match for the Latin C in borrowed words of Latin origin, e.g., цирк (circus), центр (center), and of German Z in words borrowed from German language or via German: плац (Platz), цинк (Zink).
Russian words starting with 'Ц' are rare, and almost none of them are of Slavic origin.
A notable rule of Russian orthography is that 'Ц' is seldom followed by 'ы', with the exception of the ending 'цы' of the plural number (танец–танцы) and some declensions (девица–девицы). The very few words with 'цы' inside or at the beginning are learned by schoolchildren by heart: цыган, цыкать, цыпленок, цыпочки, цып-цып, цыц. Also, there are some obsolete usages, seen in old texts, such as цынга (цинга), цыновка (циновка), панцырь (панцирь) etc.
Transliteration
A regular transliteration of 'Ц' into English is 'ts'. However in proper names (personal names, toponyms, etc.) it may also traditionally be rendered as 'c', 'z', or 'tz', depending on the national origin of the name.
