Denso vs. fitto

'Denso' and 'fitto' are Italian adjectives both meaning 'dense' or 'thick', but they are used in slightly different contexts and with nuanced meanings.

Denso

'Denso' typically refers to something that is dense, thick, or concentrated in terms of consistency or composition.
La nebbia era così densa che non riuscivo a vedere oltre il mio naso.
(The fog was so thick that I couldn't see beyond my nose.)
Il caffè espresso è molto denso e concentrato.
(Espresso coffee is very dense and concentrated.)
La crema pasticcera densa è perfetta per riempire i bignè.
(Thick pastry cream is perfect for filling cream puffs.)

Fitto

'Fitto' usually describes something that is dense in terms of closeness or frequency, often referring to groupings or patterns.
Il bosco era così fitto che i raggi del sole faticavano a penetrare.
(The forest was so dense that sunlight struggled to penetrate.)
C'era un fitto programma di eventi per il festival estivo.
(There was a packed schedule of events for the summer festival.)
La pioggia cadeva fitta e incessante.
(The rain fell heavily and incessantly.)

Summary

While both 'denso' and 'fitto' translate to 'dense' or 'thick' in English, 'denso' is more often used for physical density or concentration, whereas 'fitto' typically describes density in arrangement, frequency, or closeness of items or occurrences.