What type of radiation exposure is described as a large dose given over a short period of time?

The term "short-term dose" accurately describes a type of radiation exposure characterized by a large amount of radiation delivered over a brief timeframe. This type of exposure can lead to significant biological effects in a relatively short period, as the tissues and cells are subjected to high levels of radiation in a condensed timeframe.

In contrast, the other options refer to different types of radiation exposure scenarios. A chronic dose typically involves lower levels of radiation received over an extended period, which may lead to cumulative health effects over time but not the immediate impacts associated with short-term exposure. Long-term dose is similar, indicating protracted exposure at possibly lower levels, thus lacking the immediacy of damage characteristic of short-term high doses. Accidental exposure may imply an unintended or unexpected exposure event, but it does not specifically denote the timing and dose amount emphasized in the question. Therefore, "short-term dose" is the precise term aligning with the description of a significant dose delivered over a limited timeframe.