Sound smart: Here are some key 5G terms:

Small cells: As the name implies, these devices for providing network service are smaller than a traditional cell tower but as a result have to be placed much more closely to one another. Critical to 5G, carriers have also been using small cells to improve their 4G LTE coverage and capacity in cities
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Latency: the amount of delay, or lag in response, in a network. One of 5G's main advantages, along with faster speeds once a response has started.

Spectrum: the frequency of airwaves used to carry, among other things, cell phone signals. 5G uses a wide swath of airwaves, including higher frequencies than have been used in the past.

Millimeter wave: This ultra-high-frequency spectrum is key to getting the fastest speeds out of 5G. These signals are also fragile, traveling comparatively small distances and easily blocked by buildings and other objects. Axios