Plainly
look up a word, understand it — no rabbit hole
source
nounmeaning in plain English
Where something comes from or where you get it.
Picture a spring bubbling up— that bubbling water is the source of the river.
for example
She wouldn’t say what her source was for the drugs she was selling.
Imagine you’re thirsty and need water. The source is the faucet or bottle you drink from. Without a source, you’d be stuck with no water at all.