They lose their shape and become long strands rather than tight masses.

Today there are 237,000 crammed into a tight mass of cheap apartment blocks.

The children were a tight mass inside the circle of women.

The narrow leaves form a tight mass above ground and spread.

Ian glanced back to see a tight mass of heaving human flesh.

When a new plant is set out in its garden home its tight mass of roots must be broken up.

The rest of the herd was rushing away in a tight brown mass down the valley, the calves falling behind their dams.

Some perennials grow so well that they spread themselves into tight masses of roots.

If this tight mass of roots is not broken up at planting time, it will remain in place and never outgrow itself.

The enemy pressed close, compressing the square into a tight mass.