I believe they mean that the random variables have a common support. For example, if X ~ Unif[0,2] and Y ~ Unif[1,3], then their respective PDF's overlap in the interval [1,2], meaning the only interval where both X and Y can have common values is [1,2]. To illustrate, below is a representation of the supports of X and Y, below which is a representation of the real line.
1 Thyroid cancer is a malignant tumor of the thyroid gland. 2  Symptoms of thyroid cancer include swelling in the neck (goiter), neck pain, hoarseness, swallowing and breathing problem, swollen lymph gland in the neck.
Neck swelling can also be caused by a variety of other conditions including: 1  General infection leading to swollen lymph nodes. 2  Goiter (an enlarged thyroid gland) 3  Hereditary angioedema (a serious genetic disorder that causes periodic swelling of the throat and other areas)  Mononucleosis (a type of viral infection)