Sentence:  The development of <WSD>polony</WSD> technology is an extreme example of spatial compression; a <WSD>polony</WSD> array essentially consists of millions of distinguishable, immobilized, and femtoliter-scale "test tubes" filled with clonal DNA arising from individual DNA or RNA molecules via a single polymerase chain reaction (PCR). 
Meaning of the word marked with <WSD> tags:  A cluster of (polymers) produced by (clonal) amplification of DNA.