Sets cannot be independently defined by any arbitrary logically definable notion. Every computable number is definable, but not vice versa. It has a single easily definable tangible output. A basic form of equivalence, definable on lambda terms, is alpha equivalence. Predicate heads can also be words that are definable morphologically. The set of definable numbers is broader, but still only countable. A recent area of research concerns Borel equivalence relations and more complicated definable equivalence relations. Some properties are now given about integer relations definable in Presburger Arithmetic. Conceptualization means the process of converting vague mental images into definable concepts. Each column has associated attributes like name, units and other user definable labels. Words consist of easily definable roots and productive grammatical morphemes, most of which are suffixes. However, the induction scheme in Peano arithmetic prevents any proper cut from being definable. The limit mentioned above is user definable. In mathematics, with Berry's paradox, there arises a similar systematic ambiguity with the word "definable". The regions are also not fully definable due to colloquial use of regional labels.