staple

The Hottest Summer Shoe Trends 

The flip-flop is a much-loved summer staple, but unless your career keeps you poolside, you'll need to supplement your wardrobe with other slightly more practical options. 

From warm weather booties to chic d'Orsays pumps, here are the shoes to wear right now.

staple
〔繰り返し使われる〕不可欠な要素、必需品

The website has been a staple of the Internet. 
そのウェブサイトはインターネットの定番となっている。