To begin to open; to start to come apart—used for buds, seams, or edges that are starting to open or loosen.
梅の蕾がほころび始めた。
The plum buds have begun to open.
冬の間固かった芽が春になってやっとほころんだ。
The buds that were closed during winter finally started to open in spring.
カーテンの縁が少しほころんでいる。
The edge of the curtain is fraying a little.
To break into a smile; for one's expression to soften into a smile—often used as '顔がほころぶ'.
子供の冗談に彼女の顔がほころんだ。
Her face softened into a smile at the child's joke.
嬉しい知らせを聞いて、両親の顔がほころんだ。
Hearing the good news, the parents broke into smiles.
彼のいたずらに思わず顔がほころんだ。
I couldn't help smiling at his prank.
To come apart at the seams; to fray—referring to stitching or fabric beginning to loosen or separate.
古いコートの袖口がほころんできたので、直さなければならない。
The cuff of my old coat is starting to fray, so I need to mend it.
ぬい目がほころんでいる箇所を見つけた。
I found a place where the stitching is coming apart.
頻繁に使う部分はどうしてもほころびやすい。
Parts that are used frequently inevitably tend to fray.