Today’s Parola del giorno is the noun il viavai, which means bustle or comings and goings.
It is invariable - it has the same form for both singular and plural.
See the expression used below:
Marcello ha affittato un appartamento straordinario a Madrid per l’estate — dal suo balcone può osservare facilmente il viavai della città ogni mattina mentre prepara il caffè.
Marcello rented an amazing apartment in Madrid for the summer — from his balcony he can easily watch the comings and goings of the city every morning while he prepares his coffee.