<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31298209</termId><termName>frequency</termName><termType>PT</termType><termNote><![CDATA[ The rate or recurrence of a repeating vibration, cycle, or wave passing a fixed point in unit time. In physics, frequency is expressed in hertz units, as one cycle per second, or Hz. ]]></termNote><termCreatedDate>2026-03-30 20:19:56</termCreatedDate><relation><relationType>BT</relationType><termId>31296909</termId><termName>attributes and properties by specific type</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31298211</termId><termName>wavelength</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31363170</termId><termName>hertz</termName><termType>PT</termType></relation></term>  </Zthes>