'fused-carpelled' is a compound of 'fused' and 'carpelled'. 'fused' originates from Latin, specifically the past-participle form 'fusus' (from 'fundere'), where 'fundere' meant 'to pour' (extended to 'melt, join by heat'). 'carpelled' (from 'carpel') originates from New Latin, specifically the word 'carpelum', ultimately from Greek 'karpos', where 'karpos' meant 'fruit'.

'fused' entered English via Latin (and Old French/Middle English developments) as a verb/adjective meaning 'joined by melting' and 'carpel' was coined in botanical New Latin as 'carpelum' from Greek 'karpos'; in modern botanical English these elements combined to form the compound adjective 'fused-carpelled'.

Individually, 'fused' originally referred to 'poured/melted' (joining by fusion) and 'carpel' to 'fruit' or the fruit-bearing organ; together, over time in botanical usage the compound came to mean specifically 'having carpels that are joined together in the ovary'.