WordNet
n. British school for children aged 5-7
Wikipedia
An Infant school is a term used primarily in England and Wales. This for the education of children between the ages of four and seven years*. It is usually a small school serving a particular area.
An infant school forms part of local education provision giving primary education. In England and Wales children start at infant school between the ages of four and five in a Reception class. They sometimes attend part-time (mornings only or afternoons only) for the first term. Reception is not compulsory. (*The actual age of pupils transferring into Infant School 'Year One', is dependent on when their birthday is within the academic year. They join in the September following their birthday).
The initial Infant School year represents Key Stage 1 in the English education system. At the end of their few years in Infant school, pupils will then move on to a linked Junior school. (There are also Academy schools in both primary and secondary education.)
In some areas of England, provision of education at this age is made in Primary Schools catering for pupils aged up to eight or nine. (This is where Infants and Junior Schools are combined under a single Head Teacher or Principal. This unites both of the schools in the field of Primary Education). Under the Welsh Assembly some parts of the Welsh valleys have seen children attending infants school from the day after their third birthday.