To entrench means to establish something so firmly that it becomes very difficult to change or remove. When an idea, habit, or system becomes entrenched, it digs in deep, like roots growing thick underground.

Once troops were entrenched in deep protective ditches during battles, forcing them out became extremely difficult. Today we use the word more broadly. A company might become entrenched as the market leader, so dominant that competitors struggle to challenge it. A bad habit can become entrenched in your daily routine, making it harder to break the longer it persists.

Sometimes entrenchment is positive: entrenched traditions like celebrating birthdays or holidays connect us to the past. But often the word suggests something that should change but can't easily. When a school has an entrenched way of doing things, even good new ideas face resistance. A person with entrenched opinions refuses to consider other viewpoints, no matter what evidence is presented.

The key idea is permanence through deep establishment. Surface-level things wash away easily, but entrenched things have dug in and won't budge without serious effort. When something becomes entrenched, removing it requires more than casual attempts: it demands sustained, determined work.