As Jonas grows up, he begins to see changes in objects around him that he does not know how to explain or to give voice to. He is very confused by his new perception until the Giver in Chapter Twelve is able to explain to him that what he is seeing is actually "colour." It is shocking for us to realise that colour is one of those things--like snow and hills--that has been erased from this future world in the quest for "Sameness." Note what the Giver tells Jonas about this:
"Our people made that choice, the choice to go to Sameness. Before my time, before the previous time, back and back and back. We relinquished colour when we relinquished sunshine and did away with differences." He thought for a moment. "We gained control of many things. But we had to let go of others."
So, we can understand that colour is what Jonas is perceiving, the understanding of which has been abandoned in his community as part of the quest for Sameness. The first colour that he sees is the colour red, in the apple and then in the colour of his friend Fiona's hair. As he continues to learn and develop, he will perceive other colours.