Adolescence /ˌæd

device /dɪˈvaɪs/ noun [ C ] OBJECT
1. an object or machine which has been invented for a particular purpose
a contraceptive/electronic device
Rescuers used a special device for finding people trapped in collapsed buildings.
function /ˈfʌŋk.ʃ ə n/ noun PURPOSE
1. [ C ] the natural purpose (of something) or the duty (of a person)
The function of the veins is to carry blood to the heart.
I'm not quite sure what my function is within the company.
A thermostat performs the function of controlling temperature.
gadget /ˈgædʒ.ɪt/ noun [ C ]
a small device or machine with a particular purpose
kitchen gadgets
Have you seen this handy little gadget - it's for separating egg yolks from whites.