The name "BL Lacertae objects" remains from an original misidentification of what was thought to be a variable star discovered in 1929 in the constellation Lacerta ("the Lizard"). Using the naming convention for variable stars, this "variable star" was designated BL Lacertae.
Only later was it realized that it is not a variable star within our galaxy but rather a distant galaxy with peculiar properties (for example, radio emission), but the name stuck to the class of objects exhibiting the same features. BL Lac objects and another similar class of AGNs called Optically Violent Variables (OVVs) are sometimes referred to collectively as blazars.