strengthen

Compared meaning: to make something stronger or more solid (verb).

比较义项：使变得更强、更坚固（动词）。

• strengthen 本词

  A general-purpose verb for making anything stronger — the body, materials, relationships, arguments, or an economy. Not limited to defense; no military connotation.

  通用词，可用于使身体、材料、关系、论点或经济等任何事物变得更强；不局限于防御，没有军事色彩。

  Lifting weights every week will strengthen your arms and shoulders over time.

  每周举重会逐渐使你的手臂和肩膀变得更强壮。

• fortify

  Specifically means to make a place physically stronger to withstand attack, typically walls, borders, or military positions; carries a defensive, often military tone.

  特指使某个地方在物理上更坚固以抵御攻击，通常用于城墙、边境或军事阵地，带有防御性、常为军事语境的色彩。

  The army fortified the border before the enemy's attack reached it.

  军队在敌人的进攻到达之前加固了边境。

Both mean to make something stronger. Strengthen is a general word for the body, materials, relationships, or an economy. Fortify is more specific: it means to make a place physically stronger against attack, like walls or borders, with a defensive, military tone.

两者都表示“使更强”，但strengthen是通用词，可用于身体、结构、关系、经济等任何对象；fortify更专门，特指为抵御攻击而加固某个地方（城墙、阵地、边境），带有防御/军事色彩。fortify在其他语境中还有“（用食物、信念等）增强信心、精神”的引申义，这里不作比较。