Today  the term pre-amplifier can mean a traditional two-channel analog-only stereo pre-amplifier, but it also includes music servers and music streamers that include volume controls and preamplifiers with digital and streaming inputs. 

For example the Aurender A10 is a music server, music streamer, and pre-amplifier in one chassis and you connect it directly to an amplifier.  The A10 has an internal hard drive for music storage, so it is considered a music server.  The A10 can stream music from internet services such as Qobuz, so it is also considered a music streamer.  The A10 also has a built-in DAC and volume control which allow it to connect directly to an amplifier and act as a preamplifier. Generally we think of these as of as a music streamer with built-in volume.

Linn DSM streamers are similar but also provide analog inputs, additional digital inputs and in some units phono stages and HDMI inputs or HDMI ARC return channels. We think of these as more as a preamplifier with built-in streaming.  

Lastly, many McIntosh preamplifiers, such as the C2700 and C53 have built-in DACs and digital inputs but not streaming. To stream music, you would feed the McIntosh preamplifiers digital input from a dedicated music streaming device such as an Aurender N100C or N10 which don't have built in DACs but do supply extremely high quality digital feeds to DACs.