Sentence:  Approximate scales can be placed on near-field objects in pictures containing the <WSD>gnomon</WSD> by using an ellipse template. The w 
Meaning of the word marked with <WSD> tags:  An object such as a pillar or a rod that is used to tell time by the shadow it casts when the sun shines on it, especially the pointer on a sundial. (from mid 16th c.)