Often used, often confused. Here's some guidance and insight.
A simple trick to keep them separate
A simple way to keep them apart. (Most of the time.)
They started as same word, but their meanings have drifted apart over time.
And how did it get that name?
Why don't they call it the Merriam-Webster comma?
'Poets laureate'? 'Court-martials'? The curious history of postpositive adjectives in English.