In some 19th Century paedobaptist polemical works, I've recently seen the terms oikia and oikos distinguished. Oikos is said to mean family and oikia is said to mean household, which would include servants, etc. Generally speaking, the argument is that in Acts and elsewhere in the NT oikos is used in the household baptism passages and that's the reason why children are baptized but not household servants as would have been the case under the covenant of circumcision. Some argued that the translators of the AV erred and that oikos should have been translated as "family." Is there any validity to this? I can't recall seeing this distinction made in recent writers. Or have I missed it? I first came across it in McKay's Immersion and Immersionists. Dabney makes reference to this distinction in his ST too. I found another example in A Compend of Baptism by William Hamilton. A search in Google Books will yield several other examples. Hinton, a Baptist writer of that era, refers to this idea as "ingenious but untenable" and argues that at times the terms are sometimes used interchangeably in reference to the same house.