Son – hijo
To remember that son is pronounced ee-hoh (hijo) in Spanish, use the following mnemonic:
He had a way of dealing with his naughty son – he hosed (hijo) him down.
Hijo is masculine, so it's el hijo. Imagine someone's son invites a friend home – and it turns out to be an elephant!
NOTE: There's a feminine equivalent of hijo – hija (pronounced ee-hah), which means daughter. So if you're talking or writing about a daughter rather than a son, use la hija.