average monthly income; average monthly salary
Common in economic contexts, job listings, and statistical reports. Refers to the mean monthly earnings, typically before taxes.
The average monthly income in this area is about 300,000 yen.
The job posting lists the average monthly salary.
年収 means annual income, while 平均月収 specifically refers to the average monthly income.
月収 is simply monthly income, without the 'average' nuance. 平均月収 emphasizes the mean value.
Compound of 平均 (average) + 月収 (monthly income).