'Child' for me covers infant to teenager but feels best for the range toddler to pre-teen (if you see a sixth month old I would tend to call them a baby not a child, even though 'child' is not wrong; words can have overlapping semantic contexts). More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.