Saw a show on tv and they mentioned something called lung nodule. What is that?

Also used to be. Called a coin lesion. A solitary pulmonary nodule may be a primary cancer, or a granuloma or other benign things like a hamartoma or interlobar node. It also may the cause of "false positives" on ct-chest screening. Multiple nodules draw suspicion to traveled tumors. When very small (<5 mm), can be watched for growth; if larger, further work up including removal.
Lung Cancer. A lung nodule is nonspecific. A lung nodule can be anything from a scar to a deadly lung cancer. A nodule, usually discovered on chest xray need to be worked up to be sure it is not cancer. Ct of chest helps, old chest x-ray may show it to be a dormant scar or old granuloma from an old infection. In the end if not proven to be benign it must be biopsied. Small nodules can be followed for 2 yrs.
Lung abnormality. A lung "nodule" is a term for small abnormalities seen on xray and ct scans. Most are found to be non-cancer. If larger (~3cm or bigger), it's called a "mass". All lung nodules and masses should be evaluated and followed by referral to a comprehensive thoracic surgical cancer program. Integration into a comprehensive program saves lives and decreases unnecessary morbidity.
Size of nodule. Nodule can be benign or malignant , worrisome in smokers also the size of nodule is important to know whether it is worrisome or not.