Purchase, possession, or transportation of firearm; assault and battery of a family or household member or intimate partner; penalties. Adds to the existing definition of "family or household member" a person's intimate partner, defined in the bill as an individual who, within the previous 12 months, was in a romantic, dating, or sexual relationship with the person. The bill also provides that any person who knowingly and intentionally purchases, possesses, or transports any firearm following a misdemeanor conviction for an offense that occurred on or after July 1, 2024, for the offense of assault and battery against an intimate partner or an offense substantially similar under the laws of any other state or of the United States is guilty of a Class 1 misdemeanor. This bill is identical to SB 642.