Define the terms phonetics and phonology and explain the difference and similarity between them.
问题描述：
Define the terms phonetics and phonology and explain the difference and similarity between them.
不是翻译，因为语音学刚刚接触，手头上没有参考资料，
答
给phonetics 和 phonology下定义,并解释他们的共同点和不同点.