In its basic meaning, the term diminutive designates a noun N_D derived from a base N_B such that N_D denotes a small variety of the entity denoted by N_B. For example, German Auto ‘car’ – Autochen ‘small car’, Spanish carro ‘car’ – carrito ‘small car’. The derivation is called diminution. Diminution is a process widespread in the languages of the world.

Derived senses of the term include the following:

• The operator of diminution is called diminutive, too. Thus, German -chen and Spanish -ito/-ita are diminutive suffixes.
• Structural processes other than derivation, but with the same function, are called diminution, too. Thus Span. microclima designates a climate which is ‘small’ in the relevant sense. Diminutive compounding is exemplified by Cabecar ju ‘house’ – ju yaba (house child) ‘small house’.
• The sense of a diminutive form may expand in various directions. Rather than categorizing an entitity by its size, it may be affective, as when Span. gatito (based on gato ‘cat’) designates a cat which is not necessarily small, but beloved. Diminution also has a pragmatic function, as when a Spanish waiter offers a cafecito (based on café ‘coffee’), implying that this would prove desirable for the client.
• The analogous operation on adjectival bases, as in Span. suave ‘sweet’ – suavecito ‘delightfully sweet’, is diminution, too.
• The analogous operation on verbal bases, viz. attenuation, as in German lachen ‘laugh’ – lächeln ‘smile’, is sometimes (unnecessarily) called diminution, too.

Translation equivalents of Engl. diminution include Latin deminutio, German Deminution and Span. disminución. The Latin term means ‘lessening’, whereas Lat. diminutio means ‘breaking into small pieces’. Thus, the English and Spanish terms (which latter renders the morphological formation more explicit) are based on a misunderstanding.