Glossary » chording
an input mechanism which requires pushing more than one button simultaneously in different patterns to represent different letters or commands.
“Chording keyboards” allow rapid entry of letters and words which can allow faster typing than conventional keyboards and permits one-handed operation of keyboards.
“Chording mice” are mice with multiple buttons where clicking with more than one button is equivalent to having an additional mouse button.
Chording is a powerful tool for some users, but chording is more difficult to learn and should never be required of users. In particular, many people with arthritic conditions or other motor impairments may find chording extremely difficult (though note that one-handed operation may be extremely helpful to users without the use of one hand).