Male screw

... In Japan, screws were first seen in 1543 (Tenbun 12), when they were used as breech caps on rifles carried by Portuguese who were shipwrecked on Tanegashima Island; no evidence has been found to suggest that screws had been used in Japan prior to this time.
[Basic terms for screws]
The spiral-like protrusions mentioned above are called threads, and a thread on the outer surface of a cylinder is called a male screw, while a thread on the inner surface of a hollow cylinder is called a female screw. Also, depending on the cross-sectional shape of the thread, it can be classified as a triangular thread with a triangular cross-section, a trapezoidal thread with a trapezoidal cross-section, a square thread with a square cross-section, a sawtooth thread with a sawtooth cross-section, and a round thread with a circular cross-section (Figure 2).

*Some of the terminology explanations that mention "male screw" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…　日本では1543年(天文12)，種子島に漂着したポルトガル人がもっていた小銃の尾栓として用いられていたねじを見たのが最初といわれ，これより以前に日本でねじが使用されていた事実を示す証拠は見つかっていない。
［ねじの基本用語］
　前述のつる巻線状の突起をねじ山といい，円筒の外表面にねじ山をもつものをおねじmale screw，中空の円筒の内表面にねじ山をつけたものをめねじfemale screwという。またねじ山の断面形状により，三角形状の断面をもつ三角ねじ，台形状の台形ねじ，角形をした角ねじ，のこぎりの歯の形状をもつのこ歯ねじ，円弧状の断面をもつ丸ねじなどに分類される(図2)。…

※「male screw」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報