Last Ten Days Of The Month
End Of Month, End Of The Month
noun
The below time of month is the bottom part of the month. It's the last ten days of the month, aka the end of the month.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
四月の下旬に日本に戻って、六月上旬にまたアメリカに戻ってくる予定です。
I’m planning to go back to Japan at the end of April and come back to the states at the beginning of June.