以上术语均有策划、鼓励、协助或唆使他人犯重罪，即具有“从犯”（accessory)的含义。按传统，“从犯”曾包括accessory before the fact (事前从犯）和 accessory after the fact (事后从犯）两类。accessory before the fact 和 principal (主犯）的区别在于前者未出现而后者则出现在犯罪现场，目前美国多数州的法规已经废除此种区分而将accessory before the fact当作共犯归类为principal [1]。accessory after the fact则是指明知有人犯重罪而协助、庇护该罪犯以逃避司法惩处之从犯，现多数州已不再笼统使用此术语，而将其分为若干具体的犯罪，如干扰司法罪“obstructing  justice” 等。
 
[1 ] “The traditional distinction between accessories before the fact and principals, that accessories were not present and principals were present at the commission of the crime, is not recognized under most modem state statutes. Accessories before the fact are usually considered principals. ” Cf. Linda Picard Wood, J. D.，Merriam Webster's Dictionary of Law, at p. 6, Meniam-Webster, Incorporated, Springfield, Massachusetts (1996).
[2 ] “ Many state statutes now omit the term accessory after the fact and instead characterized the accessory as having committed a particular offense, such as obstructing justice. ”Id. at p. 6.