Transcriptionally inactive chromatin is called heterochromatin.

Answer

### Step-by-Step Solution:

1. **Understanding Chromatin**: Chromatin is a complex of DNA and proteins found in the nucleus of eukaryotic cells. It exists in two forms: euchromatin and heterochromatin.

2. **Defining Heterochromatin**: Heterochromatin is the form of chromatin that is densely packed. This dense packing makes it transcriptionally inactive, meaning that genes in this region are not expressed or transcribed into RNA.

3. **Transcription Process**: Transcription is the process by which a specific segment of DNA is copied into RNA. For transcription to occur, the chromatin must be in a less condensed state, allowing the transcription machinery to access the DNA.

4. **Comparison with Euchromatin**: In contrast to heterochromatin, euchromatin is loosely packed and is transcriptionally active. This means that genes located in euchromatin can be easily accessed and transcribed.

5. **Conclusion**: Therefore, the statement "Transcriptionally inactive chromatin is called heterochromatin" is true. Heterochromatin is characterized by its condensed structure and lack of transcriptional activity.