The difference between singer and songer
is that “singer” is a person who sings, often professionally and “songer” is a singer ; a songster.
The difference between singer and chanter
is that "singer" is a person who sings, often professionally and "chanter" is one who chants or sings.
The difference between coroner and singer
is that "coroner" is a public official who presides over an inquest into unnatural deaths, cases of treasure trove, and debris from shipwrecks and "singer" is a person who sings, often professionally.