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.
Thyroid disease can also sometimes lead to enlargement of the thyroid gland in the neck, which can cause symptoms that are directly related to the increase in size of the organ (such as difficulty swallowing and discomfort in front of the neck). Read more about thyroid disease symptoms and signs Â».