What do you call a single spaghetti noodle?
A single spaghetti noodle is quite delightfully called a spaghetto. In Italian, “i” on the end of a word means it’s plural, the “o” here means it’s singular. So this goes for all your favorite pasta: fettucino, gnocco, my personal favorite raviolo, etc. Further, you technically don’t want a panini, you want a panino. I hope this brings you as much joy as it has brought me.
A single spaghetti noodle is called spaghetto, you could also call it a noodle. For those people out there saying, "I want a panini," whenever they want a panini, you are actually supposed to say panino because it's plural.
Along these lines, "mantra" is plural. A single one is properly called a "mantrum."