How do you break down the longest medical word?

Pneumonoultramicroscopicsilicovolcanoconiosis

Here is the breakdown:

Pneumono: this word root refers to the lungs.

Ultra: meaning very small or minuscule.

Micro: meaning small or microscopic.

Scopic: meaning view or perception.

Silico: this refers to silicon or silica.

Volcano: referring to a volcano.

Coniosis: this denotes a condition.

When we put these all together, we get the meaning:

Pneumonoultramicroscopicsilicovolcanoconiosis

An extensive lung condition caused by inhaling very small particles of silica, similar to volcanic ash.