The expansion of a dendritic cell population by cell division. A dendritic cell is a cell of hematopoietic origin, typically resident in particular tissues, specialized in the uptake, processing, and transport of antigens to lymph nodes for the purpose of stimulating an immune response via T cell activation. [ http://www.ncbi.nlm.nih.gov/pubmed/18469816 http://purl.obolibrary.org/obo/CL_0000451 ]