The word "spaceful" is not commonly used in English, but it is a legitimate term meaning "having a lot of space" or "capacious." The spelling of this word can be explained using IPA phonetic transcription as "speɪsfʊl." The "a" in "space" is pronounced as "ey" in "hey," while the "ful" at the end is pronounced as "fʊl." The stress is on the first syllable, with a short "e" sound as in "pet" and a final "s" pronounced as "z."