synecdoche

A figure of speech in which the name of a part is used to stand for the whole (as hand for sailor), the whole for a part (as the law for police officer), the specific for the general (as cutthroat for assassin), the general for the specific (as thief for pickpocket), or the material for the thing made from it (as steel for sword).

In rhetoric, a figure or trope by which the whole of a thing is put for a part, or a part for the whole, as the genus for the species, or the species for the genus, etc.: as, for example, a fleet of ten sail (for ships); a master employing new hands (for workmen). Compare metonymy.

A figure or trope by which a part of a thing is put for the whole (as, fifty sail for fifty ships), or the whole for a part (as, the smiling year for spring), the species for the genus (as, cutthroat for assassin), the genus for the species (as, a creature for a man), the name of the material for the thing made, etc.

A figure or trope by which a part of a thing is put for the whole, the whole for a part, the species for the genus, the genus for the species, or the name of the material for the thing made, and similar.

The use of synecdoche; synecdochy.

substituting a more inclusive term for a less inclusive one or vice versa