# Domains & Dictionaries

> Reference guide to Egon domain codes, territorial dictionaries, and lookup tables: the allowed values of type fields in API requests and responses.

Domain dictionaries define the standardized code values and types accepted and returned by Egon request and response fields.

## Domain Dictionaries

- [Adm Code Domain](https://documentation.egon.com/docs/domains/adm-code.md): Official administrative code types returned for normalized addresses, including Belfiore, Istat, CAB, Iris, and ISO 3166. (12 values)
- [Code Domain](https://documentation.egon.com/docs/domains/code.md): Allowed values for identifier fields such as tax code, VAT code, web address, and Ateco economic activity code. (4 values)
- [Email Domain](https://documentation.egon.com/docs/domains/email.md): Classification values for email address types, differentiating standard email and Italian certified PEC. (2 values)
- [Name & Person Domain](https://documentation.egon.com/docs/domains/name.md): Subject classification types (natural person, sole proprietorship, legal entity) and gender values. (9 values)
- [Phone Domain](https://documentation.egon.com/docs/domains/phone.md): Telecommunication line types returned in enrichment responses (landline, mobile, fax). (3 values)

## Also in Reference

Complementary reference guide and data dictionary:

- [Quality Indicators](https://documentation.egon.com/docs/quality-indicators.md): Detailed validation flags (0, 1, 2/3) and outcome codes for addresses, geocoding, tax codes, and VAT.