IPA: /ˈveɪsfəl/
KK: /ˈveɪsˌfʊl/
The amount of space or quantity that a vase can hold.
She filled the vaseful with beautiful flowers from the garden.
The word 'vaseful' is formed from 'vase' (from Old French *vase*, meaning a container or vessel) and '-ful' (meaning full of). The term 'vaseful' describes something that is full of vases or has the capacity of a vase.
Think of a 'vase' as a container and remember that 'vaseful' means full of vases.