The word "lets upon" is a common phrase that means "allows for" or "permits". It is spelled as two separate words, with "lets" being the present tense of the verb "let" and "upon" being a preposition meaning "on top of" or "in close proximity to". "Lets" is pronounced as /lɛts/ with a short "e" sound and a voiced "t" sound. "Upon" is pronounced as /əˈpɒn/ with a schwa sound and a stressed "on" sound. Together, they create the frequently used phrase "lets upon".