Diploid is a cell or organism that has paired chromosomes, one from each parent. In humans, cells other than human sex cells, are diploid and have 23 pairs of chromosomes. Human sex cells (egg and sperm cells) contain a single set of chromosomes and are known as haploid.
Diploid is the term that refers to the number of each type of chromosome that an organism has. And diploid specifically means every cell in that organism has two copies of each type of chromosome. So humans are diploid, and each human has, then, in the nucleus of their cells two copies of Chromosome 1, two of number two, two of number three, all the way out to two of number 22, and then if you're a female you have two copies of the X chromosome, if you're a male you have an X and a Y. So diploid means you have two of each type of chromosome.