Yes, a CH3-(C=O)-R group is commonly referred to as an acetyl radical. Note that this is not standard IUPAC nomenclature, so names using the root acetyl are mostly common names for compounds and there are no formal rules for its use in the names of compounds.
The acetyl group is particularly important in various aspects of biology. Acetyl groups can be generated from pyruvate, the end product of glycolysis. Decarboxylation of pyruvate transfers an acetyl radical from pyruvate to a vitamin called coenzyme A (CoA), and the acetyl group from the resulting acetyl-CoA molecule can then be transferred to other substrates or used as a building block for other metabolic processes (such as fatty acid biosynthesis). One important acetylation reaction is the transfer of the acetyl group from coenzyme A to lysine residues in proteins. Acetylation of the histone proteins that help wrap and package DNA is thought to be very important for regulating gene expression and other biological processes involving DNA.