Filtering a pandas DataFrame refers to selecting rows based on a specific condition. You can filter a DataFrame using the [] operator with conditions inside, such as df[df['column'] > value], or the .query() method, like df.query('column > value').

For example, suppose you have a DataFrame df with columns "Name", "Age", and "Gender", and you want to select all rows where the values of the "Age" column are greater than 30. You can use the following code to filter the DataFrame:

# Filter the DataFrame using 
# the [] operator
df_filtered = df[df["Age"] > 30]

# Filter the DataFrame using 
# the .query() method
df_filtered = df.query("Age > 30")

You can also use the "&" (logical and) and "|" (logical or) operators to combine multiple conditions.