The Spanish word 'botarga', meaning 'theatrical costume' or 'wide trousers', has a fascinating journey through multiple languages and an interesting semantic shift. It comes from the Italian word 'bottarga', which referred to a type of caviar or fish roe. The Italian term was borrowed from Arabic 'butarjah', also meaning a type of caviar. Going even further back, the Arabic word derives from Greek 'habrotarichon', which literally meant 'delicate salted fish' - a compound word combining 'habros' (meaning 'delicate') and 'tarichon' (meaning 'salted fish').

The semantic evolution from preserved fish roe to theatrical costume is quite remarkable. This shift likely occurred because early theatrical costumes were puffy and rounded, perhaps resembling the shape of preserved fish roe sacks. The meaning then extended to include wide, baggy trousers that shared this puffy characteristic.

While 'botarga' is relatively unique in Spanish and doesn't have many common etymologically related words in modern Spanish, it's worth noting that it has maintained its specialized meaning in theatrical and clothing contexts.

While there isn't a direct English cognate for 'botarga', the English word 'bottarga' exists as a culinary term, borrowed from the same Italian source, and refers to the salted, cured fish roe that represents the original meaning of this word family. This can help English speakers remember the historical connection between the Spanish theatrical costume and its surprising origins in preserved fish products.