Question: What unit of time starts with "z"?
Paraphrase: What unit of time begins with "z"?
SPARQL (Wikidata): SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q1790144 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'z')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
Answer: zettasecond, zettasecond, zeptosecond, zeptosecond