47 CFR §64.4001

1. (a)Automatic number identification (ANI). The term automatic number identification refers to the delivery of the calling party's billing telephone number by a local exchange carrier to any interconnecting carrier for billing or routing purposes.
2. (b)Billing name and address (BNA). The term billing name and address means the name and address provided to a [LEC] by each of its local exchange customers to which the [LEC] directs bills for its services.
3. (c)Customer. The term customer means the end user to whom a local exchange carrier or interexchange carrier is providing local exchange or telephone toll service.
4. (d)Interexchange carrier (IXC). The term interexchange carrier means a telephone company that provides telephone toll service. An interexchange carrier does not include commercial mobile radio service providers as defined by federal law.
5. (e)Local exchange carrier (LEC). The term local exchange carrier means any person that is engaged in the provision of telephone exchange service or exchange access. Such term does not include a person insofar as such person is engaged in the provision of a commercial mobile service under § 332(c), except to the extent that the Commission finds that such service should be included in the definition of that term.
6. (f)Preferred interexchange carrier (PIC). The term preferred interexchange carrier means the carrier to which a customer chooses to be presubscribed for purposes of receiving intraLATA and/or interLATA and/or international toll services.