BC

• B.C., b.c., bc

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)

BC (not comparable)

1. Initialism of Before Christ.

   The Han Dynasty ruled China from 206 BC to AD 220.

   • [1739 [1735], P. Du Halde, “Geographical Obſervations on the Kingdom of Corea”, in The General History Of China‎, 2nd edition, volume IV, →OCLC, page 388:

     [...]Hi vang, King of Yen and of Corea, was defeated, taken and killed in the Year 259 before the Birth of Chriſt, according to the Chineſe Hiſtory, and Tſin vang was acknowledged for Emperor of all China by the Name of Tſin chi hoang ti.]

• The Chicago Manual of Style as well as most house styles require placing the AD before the number of the year and BC after, although in casual use either abbreviation can be found in either place.
• Some use BCE, for "Before the Common/Current/Christian Era", which is more secular in nature, to avoid potential Christian bias.
• Often written in small caps.

• BCE

• a.d., AD, A.D. (anno Domini, Anno Domini, in the year of our Lord); CE (Christian Era, Common Era, Current Era)

BC

1. British Columbia, a Canadian province.

   Coordinate terms: AB, MB, NB, NL, NS, NT, NU, ON, PE, QC, SK, YT

2. Baja California, a Mexican state.
3. Initialism of Boston College.

• (British Columbia): "B.C." is the customary abbreviation of British Columbia as used in case citations; see e.g. The Bluebook: A Uniform System of Citation, Nineteenth Edition (2010), "Geographical Terms: Australian states and Canadian provinces and territories", Table T10.2, page 438.

• BCer

• → Chinese: 卑詩／卑诗 (Bēishī)

BC (countable and uncountable, plural BCs)

1. Initialism of birth control.
2. (organic chemistry) Initialism of benzalkonium chloride.
3. (US, navy) Initialism of battlecruiser.
4. (software) Initialism of backward compatibility.

   This would be a BC-breaking change.

5. Initialism of border collie.

BC (not comparable)

1. (medicine) Initialism of board-certified.

• C.B., CB, CνB, c&b

BC

1. Abbreviation of Bacău, a county in Romania.