Ð, Unicode codepoint 208, U+00D0 is:

• Ð, a letter used in Old English and present-day Icelandic and Faroese. Its lowercase counterpart is ð.

Đ, Unicode codepoint 272, U+0110 is:

• Đ , a letter used in central South Slavic languages, Vietnamese and Northern Sami. Its lowercase counterpart is đ. It is sometimes transcripted as dj as in Franjo Tudjman. In Vietnamese, "Đ" is pronounced like the English 'D', the dash serves to distinguish it from the Vietnamese 'D' with no dash, which is pronounced like the English 'Z' or the English 'Y'.

Ɖ, Unicode codepoint 393, U+0189 is the Latin capital letter African D.

These three are all in fact separate letters which just happen to be written almost the same, much like the old Cyrillic abbreviation for the Soviet Union, СССР (transliterated SSSR), happens to resemble Latin CCCP.

A similar symbol appears as a ligature for DE ("of") in old Spanish inscriptions.