below:  Below is a lexicalization of the phrase by low, replacing an earlier on low, the opposite of on high. It was perhaps modelled on beneath. => low
early 14c., biloogh, from be- "by, about" + logh, lou, lowe "low" (see low (adj.)). Apparently a variant of earlier a-lowe (influenced by other adverbs in be-; see before), the parallel form to an-high (now on high). Beneath was the usual word; below was very rare in Middle English and gained currency only in 16c. It is frequent in Shakespeare. As a preposition from 1570s. According to Fowler, below is the opposite of above and concerns difference of level and suggests comparison of independent things. Under is the opposite of over and is concerned with superposition and subjection and suggests some interrelation.
1. Last year, economic growth tailed off to below four percent.
2. There were three moderate climbs to just below the 450 feet contour.
3. Do you think it's a bit below the belt what they're doing?
4. Down below them was the sea of upturned faces.
5. From the slope below, the wild goats bleated faintly.