What is terminal?

Terminal means it's an ending or at an end. In health, it refers to an incurable condition that will inevitably lead to the death of a patient. In transportation, it is a hub where multiple vehicles meet (buses, subway cars, trains, planes etc).
1a (1) : leading ultimately to death : fatal

• terminal cancer

(2) : approaching or close to death : being in the final stages of a fatal disease

• a terminal patient

(3) : of or relating to patients with a terminal illness

• terminal care

b : of, relating to, or occurring in a term or each term

• terminal payments

c : extremely or hopelessly severe

• terminal boredom

2a : of or relating to an end, extremity, boundary, or terminus

• a terminalpillar

b : growing at the end of a branch or stem

• a terminal bud

3a : occurring at or constituting the end of a period or series : concluding

• the terminal moments of life

b : not intended as preparation for further academic work

• a terminalcurriculum