"Personal Dictionary” means all of the words and meanings that an individual knows and shares with a particular group. The words and meanings have become part of that group’s or culture’s consensual ‘dictionary’”. Personal dictionary is thus associated with someone’s “personal culture” (see Jaan Valsiner on the relations among "culture", "sub-culture" and "personal culture")

All of us participate in multiple groups and various specialized contexts, so we acquire words and meanings that are not in a general dictionary. Some terms and meanings may be slang, or occupational, or related to a specific social group. There may even be terms that are used only in one’s family. The particular collection of terms and meanings each person knows can be referred to as their “personal dictionary”. It is personal, because it is unique – part of the person’s “idiolect”. (A person’s idiolect may include grammatical and pragmatic features, in addition to semantic meanings.) It is a dictionary because the words and meanings are authoritative for some group. They are based on the outcome of a process of creating a consensus. The consensus may be the result of the exercise of authority, or unconscious habit, or conscious and reflective discussion. But however the consensus is arrived at, people can communicate with the words because they accept – and assume others accept – the common meaning (i.e., the consensual meaning, because people accept it for the purpose of communication).

The meaning may not be in the Wordsmyth Dictionary, perhaps because the word is not widely shared. The personal dictionary is an aggregation of the words with agreements that are recognized by the diverse groups in someone’s life, and can include slang, regional dialect, family terms, etc.