That can be distinctly marked out or identified; distinguishable, discernible.
Origin
Early 17th century; earliest use found in Thomas Jackson. From classical Latin dēsignāre + -ble; compare post-classical Latin designabilis that can be specified.
designable2
/dɪˈzʌɪnəbl/
adjective
Capable of being designed, able to be designed.
Origin
Late 19th century. From design + -able. Compare earlier designable.