He ata, he tānga rānei e whai tikanga ana. Hei tauira, ko ngā pū o te reo (a, e, h ...), ko ngā tohu pūtaiao o ngā matū (pērā i te H2O mō te wai), ko ngā tohu pāngarau, pērā i te + hei tohu i te tāpiri.
A shape or a mark which has a meaning. Examples include the lettters of the alphabet, scientific and mathematical symbols.