noun
Used for a line or conceptual division separating one area, category, or side from another.
仕事と私生活のボーダーがあいまいになっている。
The boundary between work and private life is becoming blurred.
noun
Refers to the outer line, edging, or rim of an object, image, page, design, and similar things.
写真の周りに白いボーダーを入れた。
I added a white border around the photo.
noun
horizontal stripes
Clothing and fashion use; often appears as ボーダーの, ボーダー柄, or in compounds such as ボーダーシャツ. In this use it usually means horizontal stripes.
彼女はボーダーのTシャツを着ている。
She is wearing a horizontally striped T-shirt.