Question: What is "breaking of bread" in Acts 2:42?
Answer: It is commendable that we be aware of definition. We must understand words and terms in order to have the proper understandings and concepts (cf. Eph. 5: 10, 17).
The expression "breaking of bread" must be qualified. "Breaking of bread" signified the dividing of the bread cakes or loaves which were used by the oriental. Sometimes "breaking of bread" was used concerning partaking of a common meal (Mk. 6: 41; Acts 27: 35). "Breaking of bread: is also used in connection with the religious memorial called the Lord's Supper. The two elements used in this observance were unleavened bread and the fruit of the vine (Matt. 26: 17-29, elements present for the unleavened bread feast). When Jesus instituted this memorial He "brake it" (bread, dm; Matt. 26: 26).
How can one determine whether "breaking of bread" refers to a common meal or to the Lord's Supper? The answer is by the context and the way in which the expression is used. The meal in which Paul engaged and in which we have the descriptive language "break bread" was obviously a common meal (see Acts 27: 35). "Breaking bread as used in Acts 2: 46 is clearly a common meal. They broke bread "from house to house, did eat their meat with gladness and singleness of heart." However, "breaking of bread in verse 42 is used in the atmosphere of worship, as such. A good rule, then, is if "breaking of bread" is found in the environment of a meal, that is its meaning. If the expression is used in the setting of worship or the Lord's Supper, then "breaking of bread" refers to the memorial of the Lord's death.
After all has been considered, I must conclude "breaking of bread in Acts 2: 42 refers to the Lord's Supper, a regular act of worship (cf. Acts 20: 7).