旅行团 (lǚxíngtuán) is a noun meaning "tour group" or "travel group." It refers to an organized group of people traveling together, usually arranged by a travel agency. It is commonly used in tourism contexts, as in 与旅行团同行 (to travel with a tour group).
我们报了一个旅行团去云南玩。
Wǒmen bào le yī ge lǚxíng tuán qù Yúnnán wán.
We signed up for a tour group to go to Yunnan.
这个旅行团一共有二十多个人。
Zhè ge lǚxíng tuán yígòng yǒu èrshí duō ge rén.
This tour group has more than twenty people in total.
跟旅行团走比较省心,不用自己安排行程。
Gēn lǚxíng tuán zǒu bǐjiào shěngxīn, bùyòng zìjǐ ānpái xíngchéng.
Going with a tour group is less hassle since you don't have to arrange the itinerary yourself.