Computing term, the 'client' half of client-server architecture.
客户机 (kèhùjī, 'client machine') +
软件 (ruǎnjiàn, 'software'). In modern speech
客户端 (kèhùduān, 'client end') has become more common — you'll see
客户端软件 or just
客户端 (e.g. QQ
客户端,
微信客户端) more often than this older term.